[PATCH net v6 0/6] can: fix bus-off restart and device close races

[PATCH net v6 0/6] can: fix bus-off restart and device close races

[Cunhao Lu via B4 Relay]

This work started from a real failure on a production robot using a
LubanCat-5IO with an RK3588. RX continued, but the TX queue remained
stopped and subsequent sends returned ENOBUFS. The interface still
reported ERROR-ACTIVE, and the hardware indicated neither a bus-off
condition nor a pending TX request.

While testing the echo-loss fix with fault injection, I discovered a
separate race between bus-off restart and device close. This series fixes
that race; the fix for the original TX stall will follow separately.

Rockchip currently cancels restart_work in close_candev(), after freeing
the IRQ, disabling RX offload and stopping the controller. A concurrent
restart can re-enable the controller and interrupts after IRQ teardown,
and requeue timestamp work that accesses registers after runtime suspend
has disabled the controller clocks.

The CAN core checks netif_running() before scheduling or starting
recovery. A new close_candev_cancel_restart_sync() helper lets Rockchip
wait for any restart already in progress before tearing down resources.
The final close_candev() call retains cancellation and echo cleanup.

Rockchip restart masks the device's interrupts and drains active IRQ
handlers without disabling the shared interrupt line. It also drains
timestamp work before reinitializing the controller and timecounter.
Shared IRQ handling stays suspended until initialization is complete.
Timestamp locking prevents workers from rearming after deactivation and
keeps timestamp conversions consistent with timecounter updates.

The bus-off path drains TX submission and RX-side echo users before
publishing BUS_OFF, protecting the CAN core's echo flush during manual
recovery. Consumed RX FIFO entries are dropped while TX is disabled to
prevent self-transmitted frames from reaching ordinary RX. Startup
serializes carrier restoration, IRQ resumption and queue wake with a new
bus-off. The series also fixes RX offload cleanup when request_irq() fails
during open.

TX submission retains the original skb until after unlocking, so echo
preparation cannot run its socket destructor with IRQs disabled. If echo
preparation fails, drop the frame without advancing tx_head, accounting
BQL or requesting TX. This also fixes an existing failure path that
could stall TX on an empty echo slot.

The following issues were also identified during this work:

- Races in the Rockchip bus error counter cache.
- Incomplete runtime PM clock cleanup in Rockchip during removal or
  failed registration.
- Missing explicit interrupt-mask write completion before free_irq() in
  the Rockchip close path.

These three issues are outside this series. When I have time,
I will send separate patches to fix them one by one.

Hardware testing used a LubanCat-5IO running a Linux 6.18 PREEMPT_RT
kernel with v6 backported. Tests covered 2,520 request/response
exchanges over 630 seconds of continuous traffic and 100 classic CAN
loopback tests. Another 100 exchanges verified both software and
hardware TX timestamps.

All 1,000 socket-close iterations passed. Instrumentation captured
1,150 cases where the last TX skb of a closed socket was destroyed,
all after releasing tx_lock and with IRQs enabled.

All 200 injected echo clone failures dropped the frame without
submitting TX, advancing tx_head or adding BQL bytes; subsequent sends
succeeded. BUSY, occupied slots, missing echo skbs and invalid indices
were also tested, along with automatic and manual recovery using
synthetic bus-off injection. All passed.

Test-only instrumentation captured 20 restart/close and 20 close/FIFO
interleavings. No timestamp worker ran during about 300 seconds after close,
and no WARN/Oops, deadlocks or persistent TX stalls were observed.

---
Changes in v6:
- Update the can_bus_off() comment and document the running-interface
  requirement for automatic recovery.
- Explain Rockchip's use of the cancellation helper.
- Release the original TX skb after unlocking.
- Abort TX submission if echo preparation fails.
- Link to v5:
  https://patch.msgid.link/20261015-rockchip-canfd-restart-close-v5-0-ae77327037c9@qq.com

Changes in v5:
- Drop consumed RX FIFO entries under tx_lock when TX is disabled
  instead of only skipping echo filtering.
- Link to v4:
  https://patch.msgid.link/20261015-rockchip-canfd-restart-close-v4-0-ad149ff79450@qq.com

Changes in v4:
- Serialize timecounter_cyc2time() with the worker's timecounter_read()
  and startup's timecounter_init() using timestamp_lock.
- Update rkcanfd_skb_set_timestamp() to take a non-const private pointer
  and document the expanded scope of timestamp_lock.
- Link to v3:
  https://patch.msgid.link/20261014-rockchip-canfd-restart-close-v3-0-f0eb41090242@qq.com

Changes in v3:
- Replace disable_irq()/enable_irq() in Rockchip restart with device
  interrupt masking, mask readback, irq_suspended and synchronize_irq().
- Use release/acquire ordering when resuming the IRQ handler.
- Initialize timestamp delayed work once at probe and synchronously
  cancel it before restart reinitializes the timecounter.
- Balance RX offload enablement when request_irq() fails during open.
- Prevent timestamp work from reading the counter or rearming after
  deactivation, with cancellation outside the lock.
- Drain TX submission and RX-side echo users before publishing BUS_OFF,
  protecting the core's pre-restart echo flush.
- Serialize carrier restoration, IRQ enablement and queue wake with a new
  bus-off; suspend shared IRQ handling during open until startup finishes.
- Link to v2:
  https://lore.kernel.org/linux-can/tencent_82C93561D200C84C24608C80049C23EEF80A@qq.com/

Changes in v2:
- Split the series into the common checks, the cancellation helper, and
  its use in Rockchip.
- Check netif_running() after the do_set_mode capability check and before
  the restart notification, echo cleanup, and carrier update.
- Only queue automatic recovery for a running interface; keep reporting
  bus-off and make the log message match the scheduling decision.
- Add close_candev_cancel_restart_sync() in linux/can/dev.h and use it in
  close_candev() without changing the existing cleanup order.
- Replace the Rockchip mutex and closing flag with an early call to the
  helper. Drop the extra close-path IRQ synchronization and mask readback.
- Retain IRQ exclusion around hardware reinitialization in the restart
  callback.
- Link to v1:
  https://lore.kernel.org/linux-can/tencent_5802EE88434010229EDF7A53084D994C6106@qq.com/

To: Marc Kleine-Budde <mkl@pengutronix.de>
To: Vincent Mailhol <mailhol@kernel.org>
To: Heiko Stuebner <heiko@sntech.de>
To: "David S. Miller" <davem@davemloft.net>
To: Wolfgang Grandegger <wg@grandegger.com>
To: Oliver Hartkopp <socketcan@hartkopp.net>
To: kernel@pengutronix.de
To: Eric Dumazet <edumazet@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
To: Paolo Abeni <pabeni@redhat.com>
To: Simon Horman <horms@kernel.org>
To: Jonathan Corbet <corbet@lwn.net>
To: Shuah Khan <skhan@linuxfoundation.org>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-can@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Cc: netdev@vger.kernel.org
Cc: linux-doc@vger.kernel.org

---
Cunhao Lu (6):
      can: dev: prevent bus-off recovery when the interface is not running
      can: dev: add close_candev_cancel_restart_sync()
      can: rockchip_canfd: cancel bus-off restart before closing the device
      can: rockchip_canfd: prevent timestamp work from rearming after bus-off
      can: rockchip_canfd: serialize TX with bus-off and restart
      can: rockchip_canfd: serialize timecounter timestamp conversion

 Documentation/networking/can.rst                   |  6 +-
 drivers/net/can/dev/dev.c                          | 15 +++--
 drivers/net/can/rockchip/rockchip_canfd-core.c     | 67 ++++++++++++++++++++--
 drivers/net/can/rockchip/rockchip_canfd-rx.c       | 26 ++++++---
 .../net/can/rockchip/rockchip_canfd-timestamp.c    | 43 ++++++++++++--
 drivers/net/can/rockchip/rockchip_canfd-tx.c       | 40 +++++++++++--
 drivers/net/can/rockchip/rockchip_canfd.h          | 11 +++-
 include/linux/can/dev.h                            | 12 ++++
 8 files changed, 188 insertions(+), 32 deletions(-)
---
base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
change-id: 20261013-rockchip-canfd-restart-close-ebde5954f1bf

Best regards,
--  
Cunhao Lu <1579567540@qq.com>

[PATCH net v6 0/6] can: fix bus-off restart and device close races

[Cunhao Lu via B4 Relay]

This work started from a real failure on a production robot using a
LubanCat-5IO with an RK3588. RX continued, but the TX queue remained
stopped and subsequent sends returned ENOBUFS. The interface still
reported ERROR-ACTIVE, and the hardware indicated neither a bus-off
condition nor a pending TX request.

While testing the echo-loss fix with fault injection, I discovered a
separate race between bus-off restart and device close. This series fixes
that race; the fix for the original TX stall will follow separately.

Rockchip currently cancels restart_work in close_candev(), after freeing
the IRQ, disabling RX offload and stopping the controller. A concurrent
restart can re-enable the controller and interrupts after IRQ teardown,
and requeue timestamp work that accesses registers after runtime suspend
has disabled the controller clocks.

The CAN core checks netif_running() before scheduling or starting
recovery. A new close_candev_cancel_restart_sync() helper lets Rockchip
wait for any restart already in progress before tearing down resources.
The final close_candev() call retains cancellation and echo cleanup.

Rockchip restart masks the device's interrupts and drains active IRQ
handlers without disabling the shared interrupt line. It also drains
timestamp work before reinitializing the controller and timecounter.
Shared IRQ handling stays suspended until initialization is complete.
Timestamp locking prevents workers from rearming after deactivation and
keeps timestamp conversions consistent with timecounter updates.

The bus-off path drains TX submission and RX-side echo users before
publishing BUS_OFF, protecting the CAN core's echo flush during manual
recovery. Consumed RX FIFO entries are dropped while TX is disabled to
prevent self-transmitted frames from reaching ordinary RX. Startup
serializes carrier restoration, IRQ resumption and queue wake with a new
bus-off. The series also fixes RX offload cleanup when request_irq() fails
during open.

TX submission retains the original skb until after unlocking, so echo
preparation cannot run its socket destructor with IRQs disabled. If echo
preparation fails, drop the frame without advancing tx_head, accounting
BQL or requesting TX. This also fixes an existing failure path that
could stall TX on an empty echo slot.

The following issues were also identified during this work:

- Races in the Rockchip bus error counter cache.
- Incomplete runtime PM clock cleanup in Rockchip during removal or
  failed registration.
- Missing explicit interrupt-mask write completion before free_irq() in
  the Rockchip close path.

These three issues are outside this series. When I have time,
I will send separate patches to fix them one by one.

Hardware testing used a LubanCat-5IO running a Linux 6.18 PREEMPT_RT
kernel with v6 backported. Tests covered 2,520 request/response
exchanges over 630 seconds of continuous traffic and 100 classic CAN
loopback tests. Another 100 exchanges verified both software and
hardware TX timestamps.

All 1,000 socket-close iterations passed. Instrumentation captured
1,150 cases where the last TX skb of a closed socket was destroyed,
all after releasing tx_lock and with IRQs enabled.

All 200 injected echo clone failures dropped the frame without
submitting TX, advancing tx_head or adding BQL bytes; subsequent sends
succeeded. BUSY, occupied slots, missing echo skbs and invalid indices
were also tested, along with automatic and manual recovery using
synthetic bus-off injection. All passed.

Test-only instrumentation captured 20 restart/close and 20 close/FIFO
interleavings. No timestamp worker ran during about 300 seconds after close,
and no WARN/Oops, deadlocks or persistent TX stalls were observed.

---
Changes in v6:
- Update the can_bus_off() comment and document the running-interface
  requirement for automatic recovery.
- Explain Rockchip's use of the cancellation helper.
- Release the original TX skb after unlocking.
- Abort TX submission if echo preparation fails.
- Link to v5:
  https://patch.msgid.link/20261015-rockchip-canfd-restart-close-v5-0-ae77327037c9@qq.com

Changes in v5:
- Drop consumed RX FIFO entries under tx_lock when TX is disabled
  instead of only skipping echo filtering.
- Link to v4:
  https://patch.msgid.link/20261015-rockchip-canfd-restart-close-v4-0-ad149ff79450@qq.com

Changes in v4:
- Serialize timecounter_cyc2time() with the worker's timecounter_read()
  and startup's timecounter_init() using timestamp_lock.
- Update rkcanfd_skb_set_timestamp() to take a non-const private pointer
  and document the expanded scope of timestamp_lock.
- Link to v3:
  https://patch.msgid.link/20261014-rockchip-canfd-restart-close-v3-0-f0eb41090242@qq.com

Changes in v3:
- Replace disable_irq()/enable_irq() in Rockchip restart with device
  interrupt masking, mask readback, irq_suspended and synchronize_irq().
- Use release/acquire ordering when resuming the IRQ handler.
- Initialize timestamp delayed work once at probe and synchronously
  cancel it before restart reinitializes the timecounter.
- Balance RX offload enablement when request_irq() fails during open.
- Prevent timestamp work from reading the counter or rearming after
  deactivation, with cancellation outside the lock.
- Drain TX submission and RX-side echo users before publishing BUS_OFF,
  protecting the core's pre-restart echo flush.
- Serialize carrier restoration, IRQ enablement and queue wake with a new
  bus-off; suspend shared IRQ handling during open until startup finishes.
- Link to v2:
  https://lore.kernel.org/linux-can/tencent_82C93561D200C84C24608C80049C23EEF80A@qq.com/

Changes in v2:
- Split the series into the common checks, the cancellation helper, and
  its use in Rockchip.
- Check netif_running() after the do_set_mode capability check and before
  the restart notification, echo cleanup, and carrier update.
- Only queue automatic recovery for a running interface; keep reporting
  bus-off and make the log message match the scheduling decision.
- Add close_candev_cancel_restart_sync() in linux/can/dev.h and use it in
  close_candev() without changing the existing cleanup order.
- Replace the Rockchip mutex and closing flag with an early call to the
  helper. Drop the extra close-path IRQ synchronization and mask readback.
- Retain IRQ exclusion around hardware reinitialization in the restart
  callback.
- Link to v1:
  https://lore.kernel.org/linux-can/tencent_5802EE88434010229EDF7A53084D994C6106@qq.com/

To: Marc Kleine-Budde <mkl@pengutronix.de>
To: Vincent Mailhol <mailhol@kernel.org>
To: Heiko Stuebner <heiko@sntech.de>
To: "David S. Miller" <davem@davemloft.net>
To: Wolfgang Grandegger <wg@grandegger.com>
To: Oliver Hartkopp <socketcan@hartkopp.net>
To: kernel@pengutronix.de
To: Eric Dumazet <edumazet@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
To: Paolo Abeni <pabeni@redhat.com>
To: Simon Horman <horms@kernel.org>
To: Jonathan Corbet <corbet@lwn.net>
To: Shuah Khan <skhan@linuxfoundation.org>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-can@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Cc: netdev@vger.kernel.org
Cc: linux-doc@vger.kernel.org

---
Cunhao Lu (6):
      can: dev: prevent bus-off recovery when the interface is not running
      can: dev: add close_candev_cancel_restart_sync()
      can: rockchip_canfd: cancel bus-off restart before closing the device
      can: rockchip_canfd: prevent timestamp work from rearming after bus-off
      can: rockchip_canfd: serialize TX with bus-off and restart
      can: rockchip_canfd: serialize timecounter timestamp conversion

 Documentation/networking/can.rst                   |  6 +-
 drivers/net/can/dev/dev.c                          | 15 +++--
 drivers/net/can/rockchip/rockchip_canfd-core.c     | 67 ++++++++++++++++++++--
 drivers/net/can/rockchip/rockchip_canfd-rx.c       | 26 ++++++---
 .../net/can/rockchip/rockchip_canfd-timestamp.c    | 43 ++++++++++++--
 drivers/net/can/rockchip/rockchip_canfd-tx.c       | 40 +++++++++++--
 drivers/net/can/rockchip/rockchip_canfd.h          | 11 +++-
 include/linux/can/dev.h                            | 12 ++++
 8 files changed, 188 insertions(+), 32 deletions(-)
---
base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
change-id: 20261013-rockchip-canfd-restart-close-ebde5954f1bf

Best regards,
--  
Cunhao Lu <1579567540@qq.com>



_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

[PATCH net v6 0/6] can: fix bus-off restart and device close races

[Cunhao Lu]

This work started from a real failure on a production robot using a
LubanCat-5IO with an RK3588. RX continued, but the TX queue remained
stopped and subsequent sends returned ENOBUFS. The interface still
reported ERROR-ACTIVE, and the hardware indicated neither a bus-off
condition nor a pending TX request.

While testing the echo-loss fix with fault injection, I discovered a
separate race between bus-off restart and device close. This series fixes
that race; the fix for the original TX stall will follow separately.

Rockchip currently cancels restart_work in close_candev(), after freeing
the IRQ, disabling RX offload and stopping the controller. A concurrent
restart can re-enable the controller and interrupts after IRQ teardown,
and requeue timestamp work that accesses registers after runtime suspend
has disabled the controller clocks.

The CAN core checks netif_running() before scheduling or starting
recovery. A new close_candev_cancel_restart_sync() helper lets Rockchip
wait for any restart already in progress before tearing down resources.
The final close_candev() call retains cancellation and echo cleanup.

Rockchip restart masks the device's interrupts and drains active IRQ
handlers without disabling the shared interrupt line. It also drains
timestamp work before reinitializing the controller and timecounter.
Shared IRQ handling stays suspended until initialization is complete.
Timestamp locking prevents workers from rearming after deactivation and
keeps timestamp conversions consistent with timecounter updates.

The bus-off path drains TX submission and RX-side echo users before
publishing BUS_OFF, protecting the CAN core's echo flush during manual
recovery. Consumed RX FIFO entries are dropped while TX is disabled to
prevent self-transmitted frames from reaching ordinary RX. Startup
serializes carrier restoration, IRQ resumption and queue wake with a new
bus-off. The series also fixes RX offload cleanup when request_irq() fails
during open.

TX submission retains the original skb until after unlocking, so echo
preparation cannot run its socket destructor with IRQs disabled. If echo
preparation fails, drop the frame without advancing tx_head, accounting
BQL or requesting TX. This also fixes an existing failure path that
could stall TX on an empty echo slot.

The following issues were also identified during this work:

- Races in the Rockchip bus error counter cache.
- Incomplete runtime PM clock cleanup in Rockchip during removal or
  failed registration.
- Missing explicit interrupt-mask write completion before free_irq() in
  the Rockchip close path.

These three issues are outside this series. When I have time,
I will send separate patches to fix them one by one.

Hardware testing used a LubanCat-5IO running a Linux 6.18 PREEMPT_RT
kernel with v6 backported. Tests covered 2,520 request/response
exchanges over 630 seconds of continuous traffic and 100 classic CAN
loopback tests. Another 100 exchanges verified both software and
hardware TX timestamps.

All 1,000 socket-close iterations passed. Instrumentation captured
1,150 cases where the last TX skb of a closed socket was destroyed,
all after releasing tx_lock and with IRQs enabled.

All 200 injected echo clone failures dropped the frame without
submitting TX, advancing tx_head or adding BQL bytes; subsequent sends
succeeded. BUSY, occupied slots, missing echo skbs and invalid indices
were also tested, along with automatic and manual recovery using
synthetic bus-off injection. All passed.

Test-only instrumentation captured 20 restart/close and 20 close/FIFO
interleavings. No timestamp worker ran during about 300 seconds after close,
and no WARN/Oops, deadlocks or persistent TX stalls were observed.

---
Changes in v6:
- Update the can_bus_off() comment and document the running-interface
  requirement for automatic recovery.
- Explain Rockchip's use of the cancellation helper.
- Release the original TX skb after unlocking.
- Abort TX submission if echo preparation fails.
- Link to v5:
  https://patch.msgid.link/20261015-rockchip-canfd-restart-close-v5-0-ae77327037c9@qq.com

Changes in v5:
- Drop consumed RX FIFO entries under tx_lock when TX is disabled
  instead of only skipping echo filtering.
- Link to v4:
  https://patch.msgid.link/20261015-rockchip-canfd-restart-close-v4-0-ad149ff79450@qq.com

Changes in v4:
- Serialize timecounter_cyc2time() with the worker's timecounter_read()
  and startup's timecounter_init() using timestamp_lock.
- Update rkcanfd_skb_set_timestamp() to take a non-const private pointer
  and document the expanded scope of timestamp_lock.
- Link to v3:
  https://patch.msgid.link/20261014-rockchip-canfd-restart-close-v3-0-f0eb41090242@qq.com

Changes in v3:
- Replace disable_irq()/enable_irq() in Rockchip restart with device
  interrupt masking, mask readback, irq_suspended and synchronize_irq().
- Use release/acquire ordering when resuming the IRQ handler.
- Initialize timestamp delayed work once at probe and synchronously
  cancel it before restart reinitializes the timecounter.
- Balance RX offload enablement when request_irq() fails during open.
- Prevent timestamp work from reading the counter or rearming after
  deactivation, with cancellation outside the lock.
- Drain TX submission and RX-side echo users before publishing BUS_OFF,
  protecting the core's pre-restart echo flush.
- Serialize carrier restoration, IRQ enablement and queue wake with a new
  bus-off; suspend shared IRQ handling during open until startup finishes.
- Link to v2:
  https://lore.kernel.org/linux-can/tencent_82C93561D200C84C24608C80049C23EEF80A@qq.com/

Changes in v2:
- Split the series into the common checks, the cancellation helper, and
  its use in Rockchip.
- Check netif_running() after the do_set_mode capability check and before
  the restart notification, echo cleanup, and carrier update.
- Only queue automatic recovery for a running interface; keep reporting
  bus-off and make the log message match the scheduling decision.
- Add close_candev_cancel_restart_sync() in linux/can/dev.h and use it in
  close_candev() without changing the existing cleanup order.
- Replace the Rockchip mutex and closing flag with an early call to the
  helper. Drop the extra close-path IRQ synchronization and mask readback.
- Retain IRQ exclusion around hardware reinitialization in the restart
  callback.
- Link to v1:
  https://lore.kernel.org/linux-can/tencent_5802EE88434010229EDF7A53084D994C6106@qq.com/

To: Marc Kleine-Budde <mkl@pengutronix.de>
To: Vincent Mailhol <mailhol@kernel.org>
To: Heiko Stuebner <heiko@sntech.de>
To: "David S. Miller" <davem@davemloft.net>
To: Wolfgang Grandegger <wg@grandegger.com>
To: Oliver Hartkopp <socketcan@hartkopp.net>
To: kernel@pengutronix.de
To: Eric Dumazet <edumazet@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
To: Paolo Abeni <pabeni@redhat.com>
To: Simon Horman <horms@kernel.org>
To: Jonathan Corbet <corbet@lwn.net>
To: Shuah Khan <skhan@linuxfoundation.org>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-can@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Cc: netdev@vger.kernel.org
Cc: linux-doc@vger.kernel.org

---
Cunhao Lu (6):
      can: dev: prevent bus-off recovery when the interface is not running
      can: dev: add close_candev_cancel_restart_sync()
      can: rockchip_canfd: cancel bus-off restart before closing the device
      can: rockchip_canfd: prevent timestamp work from rearming after bus-off
      can: rockchip_canfd: serialize TX with bus-off and restart
      can: rockchip_canfd: serialize timecounter timestamp conversion

 Documentation/networking/can.rst                   |  6 +-
 drivers/net/can/dev/dev.c                          | 15 +++--
 drivers/net/can/rockchip/rockchip_canfd-core.c     | 67 ++++++++++++++++++++--
 drivers/net/can/rockchip/rockchip_canfd-rx.c       | 26 ++++++---
 .../net/can/rockchip/rockchip_canfd-timestamp.c    | 43 ++++++++++++--
 drivers/net/can/rockchip/rockchip_canfd-tx.c       | 40 +++++++++++--
 drivers/net/can/rockchip/rockchip_canfd.h          | 11 +++-
 include/linux/can/dev.h                            | 12 ++++
 8 files changed, 188 insertions(+), 32 deletions(-)
---
base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
change-id: 20261013-rockchip-canfd-restart-close-ebde5954f1bf

Best regards,
--  
Cunhao Lu <1579567540@qq.com>

[PATCH net v6 1/6] can: dev: prevent bus-off recovery when the interface is not running

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The networking core clears __LINK_STATE_START before calling ndo_stop(),
but CAN bus-off recovery neither checks this state before queuing work
nor before calling the driver's restart callback. Recovery can therefore
be queued or started after the interface has begun closing, potentially
re-enabling hardware while the driver is tearing it down.

Check netif_running() in can_restart() before flushing echo skbs, sending
the restart notification or enabling the carrier. Keep the existing
unsupported-operation check first. In can_bus_off(), only schedule
recovery for a running interface and make the log message reflect that
decision. Keep reporting bus-off and disabling the carrier.

These checks do not wait for recovery that has already passed the check,
nor serialize the check with work submission. Drivers still need to
cancel restart work before tearing down resources and quiesce its
producers before their final cleanup.

Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Update the can_bus_off() comment and document the running-interface
  requirement for automatic recovery.
---
 Documentation/networking/can.rst |  6 ++++--
 drivers/net/can/dev/dev.c        | 11 ++++++++---
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst
index 536ff411da1d1..861397e4ce906 100644
--- a/Documentation/networking/can.rst
+++ b/Documentation/networking/can.rst
@@ -1298,7 +1298,8 @@ More info to the above output:
 	Automatic restart delay time. If set to a non-zero value, a
 	restart of the CAN controller will be triggered automatically
 	in case of a bus-off condition after the specified delay time
-	in milliseconds. By default it's off.
+	in milliseconds, provided the interface is running. By default
+	it's off.
 
 "bitrate 125000 sample-point 0.875"
 	Shows the real bit-rate in bits/sec and the sample-point in the
@@ -1372,7 +1373,8 @@ before you can start it to avoid error-prone default settings::
 A device may enter the "bus-off" state if too many errors occurred on
 the CAN bus. Then no more messages are received or sent. An automatic
 bus-off recovery can be enabled by setting the "restart-ms" to a
-non-zero value, e.g.::
+non-zero value. Recovery is only scheduled and started while the
+interface is running, e.g.::
 
     $ ip link set canX type can restart-ms 100
 
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index 769745e22a3c7..d5cb22db2a346 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -198,6 +198,9 @@ static int can_restart(struct net_device *dev)
 	if (!priv->do_set_mode)
 		return -EOPNOTSUPP;
 
+	if (!netif_running(dev))
+		return -ENETDOWN;
+
 	if (netif_carrier_ok(dev))
 		netdev_err(dev, "Attempt to restart for bus-off recovery, but carrier is OK?\n");
 
@@ -259,13 +262,15 @@ int can_restart_now(struct net_device *dev)
  *
  * This functions should be called when the device goes bus-off to
  * tell the netif layer that no more packets can be sent or received.
- * If enabled, a timer is started to trigger bus-off recovery.
+ * If automatic recovery is enabled and the interface is running,
+ * delayed work is scheduled to trigger bus-off recovery.
  */
 void can_bus_off(struct net_device *dev)
 {
 	struct can_priv *priv = netdev_priv(dev);
+	const bool restart = priv->restart_ms && netif_running(dev);
 
-	if (priv->restart_ms)
+	if (restart)
 		netdev_info(dev, "bus-off, scheduling restart in %d ms\n",
 			    priv->restart_ms);
 	else
@@ -273,7 +278,7 @@ void can_bus_off(struct net_device *dev)
 
 	netif_carrier_off(dev);
 
-	if (priv->restart_ms)
+	if (restart)
 		schedule_delayed_work(&priv->restart_work,
 				      msecs_to_jiffies(priv->restart_ms));
 }

-- 
2.34.1

[PATCH net v6 1/6] can: dev: prevent bus-off recovery when the interface is not running

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The networking core clears __LINK_STATE_START before calling ndo_stop(),
but CAN bus-off recovery neither checks this state before queuing work
nor before calling the driver's restart callback. Recovery can therefore
be queued or started after the interface has begun closing, potentially
re-enabling hardware while the driver is tearing it down.

Check netif_running() in can_restart() before flushing echo skbs, sending
the restart notification or enabling the carrier. Keep the existing
unsupported-operation check first. In can_bus_off(), only schedule
recovery for a running interface and make the log message reflect that
decision. Keep reporting bus-off and disabling the carrier.

These checks do not wait for recovery that has already passed the check,
nor serialize the check with work submission. Drivers still need to
cancel restart work before tearing down resources and quiesce its
producers before their final cleanup.

Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Update the can_bus_off() comment and document the running-interface
  requirement for automatic recovery.
---
 Documentation/networking/can.rst |  6 ++++--
 drivers/net/can/dev/dev.c        | 11 ++++++++---
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst
index 536ff411da1d1..861397e4ce906 100644
--- a/Documentation/networking/can.rst
+++ b/Documentation/networking/can.rst
@@ -1298,7 +1298,8 @@ More info to the above output:
 	Automatic restart delay time. If set to a non-zero value, a
 	restart of the CAN controller will be triggered automatically
 	in case of a bus-off condition after the specified delay time
-	in milliseconds. By default it's off.
+	in milliseconds, provided the interface is running. By default
+	it's off.
 
 "bitrate 125000 sample-point 0.875"
 	Shows the real bit-rate in bits/sec and the sample-point in the
@@ -1372,7 +1373,8 @@ before you can start it to avoid error-prone default settings::
 A device may enter the "bus-off" state if too many errors occurred on
 the CAN bus. Then no more messages are received or sent. An automatic
 bus-off recovery can be enabled by setting the "restart-ms" to a
-non-zero value, e.g.::
+non-zero value. Recovery is only scheduled and started while the
+interface is running, e.g.::
 
     $ ip link set canX type can restart-ms 100
 
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index 769745e22a3c7..d5cb22db2a346 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -198,6 +198,9 @@ static int can_restart(struct net_device *dev)
 	if (!priv->do_set_mode)
 		return -EOPNOTSUPP;
 
+	if (!netif_running(dev))
+		return -ENETDOWN;
+
 	if (netif_carrier_ok(dev))
 		netdev_err(dev, "Attempt to restart for bus-off recovery, but carrier is OK?\n");
 
@@ -259,13 +262,15 @@ int can_restart_now(struct net_device *dev)
  *
  * This functions should be called when the device goes bus-off to
  * tell the netif layer that no more packets can be sent or received.
- * If enabled, a timer is started to trigger bus-off recovery.
+ * If automatic recovery is enabled and the interface is running,
+ * delayed work is scheduled to trigger bus-off recovery.
  */
 void can_bus_off(struct net_device *dev)
 {
 	struct can_priv *priv = netdev_priv(dev);
+	const bool restart = priv->restart_ms && netif_running(dev);
 
-	if (priv->restart_ms)
+	if (restart)
 		netdev_info(dev, "bus-off, scheduling restart in %d ms\n",
 			    priv->restart_ms);
 	else
@@ -273,7 +278,7 @@ void can_bus_off(struct net_device *dev)
 
 	netif_carrier_off(dev);
 
-	if (priv->restart_ms)
+	if (restart)
 		schedule_delayed_work(&priv->restart_work,
 				      msecs_to_jiffies(priv->restart_ms));
 }

-- 
2.34.1



_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

[PATCH net v6 1/6] can: dev: prevent bus-off recovery when the interface is not running

[Cunhao Lu]

The networking core clears __LINK_STATE_START before calling ndo_stop(),
but CAN bus-off recovery neither checks this state before queuing work
nor before calling the driver's restart callback. Recovery can therefore
be queued or started after the interface has begun closing, potentially
re-enabling hardware while the driver is tearing it down.

Check netif_running() in can_restart() before flushing echo skbs, sending
the restart notification or enabling the carrier. Keep the existing
unsupported-operation check first. In can_bus_off(), only schedule
recovery for a running interface and make the log message reflect that
decision. Keep reporting bus-off and disabling the carrier.

These checks do not wait for recovery that has already passed the check,
nor serialize the check with work submission. Drivers still need to
cancel restart work before tearing down resources and quiesce its
producers before their final cleanup.

Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Update the can_bus_off() comment and document the running-interface
  requirement for automatic recovery.
---
 Documentation/networking/can.rst |  6 ++++--
 drivers/net/can/dev/dev.c        | 11 ++++++++---
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst
index 536ff411da1d1..861397e4ce906 100644
--- a/Documentation/networking/can.rst
+++ b/Documentation/networking/can.rst
@@ -1298,7 +1298,8 @@ More info to the above output:
 	Automatic restart delay time. If set to a non-zero value, a
 	restart of the CAN controller will be triggered automatically
 	in case of a bus-off condition after the specified delay time
-	in milliseconds. By default it's off.
+	in milliseconds, provided the interface is running. By default
+	it's off.
 
 "bitrate 125000 sample-point 0.875"
 	Shows the real bit-rate in bits/sec and the sample-point in the
@@ -1372,7 +1373,8 @@ before you can start it to avoid error-prone default settings::
 A device may enter the "bus-off" state if too many errors occurred on
 the CAN bus. Then no more messages are received or sent. An automatic
 bus-off recovery can be enabled by setting the "restart-ms" to a
-non-zero value, e.g.::
+non-zero value. Recovery is only scheduled and started while the
+interface is running, e.g.::
 
     $ ip link set canX type can restart-ms 100
 
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index 769745e22a3c7..d5cb22db2a346 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -198,6 +198,9 @@ static int can_restart(struct net_device *dev)
 	if (!priv->do_set_mode)
 		return -EOPNOTSUPP;
 
+	if (!netif_running(dev))
+		return -ENETDOWN;
+
 	if (netif_carrier_ok(dev))
 		netdev_err(dev, "Attempt to restart for bus-off recovery, but carrier is OK?\n");
 
@@ -259,13 +262,15 @@ int can_restart_now(struct net_device *dev)
  *
  * This functions should be called when the device goes bus-off to
  * tell the netif layer that no more packets can be sent or received.
- * If enabled, a timer is started to trigger bus-off recovery.
+ * If automatic recovery is enabled and the interface is running,
+ * delayed work is scheduled to trigger bus-off recovery.
  */
 void can_bus_off(struct net_device *dev)
 {
 	struct can_priv *priv = netdev_priv(dev);
+	const bool restart = priv->restart_ms && netif_running(dev);
 
-	if (priv->restart_ms)
+	if (restart)
 		netdev_info(dev, "bus-off, scheduling restart in %d ms\n",
 			    priv->restart_ms);
 	else
@@ -273,7 +278,7 @@ void can_bus_off(struct net_device *dev)
 
 	netif_carrier_off(dev);
 
-	if (priv->restart_ms)
+	if (restart)
 		schedule_delayed_work(&priv->restart_work,
 				      msecs_to_jiffies(priv->restart_ms));
 }

-- 
2.34.1

[PATCH net v6 2/6] can: dev: add close_candev_cancel_restart_sync()

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

Drivers may need to wait for bus-off recovery before tearing down the
IRQ and hardware resources used by their restart callback. Calling
close_candev() at that point also flushes echo skbs, which belongs after
the driver has quiesced the users of those buffers.

Add close_candev_cancel_restart_sync() in linux/can/dev.h so drivers can
cancel the core restart work separately, without accessing can_priv's
work item directly. The helper only cancels restart work; callers must
still stop its producers and call close_candev() for the final cleanup.

Use the helper in close_candev(), preserving its existing cancellation
and echo cleanup order.

The following Rockchip fix uses the helper at the start of rkcanfd_stop()
to wait for recovery before IRQ teardown, leaving echo cleanup to
close_candev().

Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Describe the helper's use by the following Rockchip fix.
---
 drivers/net/can/dev/dev.c |  4 +---
 include/linux/can/dev.h   | 12 ++++++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index d5cb22db2a346..a5f4ce7cb5264 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -535,9 +535,7 @@ EXPORT_SYMBOL_GPL(of_can_transceiver);
  */
 void close_candev(struct net_device *dev)
 {
-	struct can_priv *priv = netdev_priv(dev);
-
-	cancel_delayed_work_sync(&priv->restart_work);
+	close_candev_cancel_restart_sync(dev);
 	can_flush_echo_skb(dev);
 }
 EXPORT_SYMBOL_GPL(close_candev);
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 6d0710d6f571d..a277d12332f15 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -22,6 +22,7 @@
 #include <linux/can/skb.h>
 #include <linux/ethtool.h>
 #include <linux/netdevice.h>
+#include <linux/workqueue.h>
 
 /*
  * CAN mode
@@ -115,6 +116,17 @@ struct can_priv *safe_candev_priv(struct net_device *dev);
 
 int open_candev(struct net_device *dev);
 void close_candev(struct net_device *dev);
+
+/* Cancel bus-off restart before tearing down resources used by the restart
+ * callback. The driver must still call close_candev() for the final cleanup.
+ */
+static inline void close_candev_cancel_restart_sync(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	cancel_delayed_work_sync(&priv->restart_work);
+}
+
 void can_set_default_mtu(struct net_device *dev);
 void can_set_cap_info(struct net_device *dev);
 int __must_check can_set_static_ctrlmode(struct net_device *dev,

-- 
2.34.1

[PATCH net v6 2/6] can: dev: add close_candev_cancel_restart_sync()

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

Drivers may need to wait for bus-off recovery before tearing down the
IRQ and hardware resources used by their restart callback. Calling
close_candev() at that point also flushes echo skbs, which belongs after
the driver has quiesced the users of those buffers.

Add close_candev_cancel_restart_sync() in linux/can/dev.h so drivers can
cancel the core restart work separately, without accessing can_priv's
work item directly. The helper only cancels restart work; callers must
still stop its producers and call close_candev() for the final cleanup.

Use the helper in close_candev(), preserving its existing cancellation
and echo cleanup order.

The following Rockchip fix uses the helper at the start of rkcanfd_stop()
to wait for recovery before IRQ teardown, leaving echo cleanup to
close_candev().

Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Describe the helper's use by the following Rockchip fix.
---
 drivers/net/can/dev/dev.c |  4 +---
 include/linux/can/dev.h   | 12 ++++++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index d5cb22db2a346..a5f4ce7cb5264 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -535,9 +535,7 @@ EXPORT_SYMBOL_GPL(of_can_transceiver);
  */
 void close_candev(struct net_device *dev)
 {
-	struct can_priv *priv = netdev_priv(dev);
-
-	cancel_delayed_work_sync(&priv->restart_work);
+	close_candev_cancel_restart_sync(dev);
 	can_flush_echo_skb(dev);
 }
 EXPORT_SYMBOL_GPL(close_candev);
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 6d0710d6f571d..a277d12332f15 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -22,6 +22,7 @@
 #include <linux/can/skb.h>
 #include <linux/ethtool.h>
 #include <linux/netdevice.h>
+#include <linux/workqueue.h>
 
 /*
  * CAN mode
@@ -115,6 +116,17 @@ struct can_priv *safe_candev_priv(struct net_device *dev);
 
 int open_candev(struct net_device *dev);
 void close_candev(struct net_device *dev);
+
+/* Cancel bus-off restart before tearing down resources used by the restart
+ * callback. The driver must still call close_candev() for the final cleanup.
+ */
+static inline void close_candev_cancel_restart_sync(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	cancel_delayed_work_sync(&priv->restart_work);
+}
+
 void can_set_default_mtu(struct net_device *dev);
 void can_set_cap_info(struct net_device *dev);
 int __must_check can_set_static_ctrlmode(struct net_device *dev,

-- 
2.34.1



_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

[PATCH net v6 2/6] can: dev: add close_candev_cancel_restart_sync()

[Cunhao Lu]

Drivers may need to wait for bus-off recovery before tearing down the
IRQ and hardware resources used by their restart callback. Calling
close_candev() at that point also flushes echo skbs, which belongs after
the driver has quiesced the users of those buffers.

Add close_candev_cancel_restart_sync() in linux/can/dev.h so drivers can
cancel the core restart work separately, without accessing can_priv's
work item directly. The helper only cancels restart work; callers must
still stop its producers and call close_candev() for the final cleanup.

Use the helper in close_candev(), preserving its existing cancellation
and echo cleanup order.

The following Rockchip fix uses the helper at the start of rkcanfd_stop()
to wait for recovery before IRQ teardown, leaving echo cleanup to
close_candev().

Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Describe the helper's use by the following Rockchip fix.
---
 drivers/net/can/dev/dev.c |  4 +---
 include/linux/can/dev.h   | 12 ++++++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index d5cb22db2a346..a5f4ce7cb5264 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -535,9 +535,7 @@ EXPORT_SYMBOL_GPL(of_can_transceiver);
  */
 void close_candev(struct net_device *dev)
 {
-	struct can_priv *priv = netdev_priv(dev);
-
-	cancel_delayed_work_sync(&priv->restart_work);
+	close_candev_cancel_restart_sync(dev);
 	can_flush_echo_skb(dev);
 }
 EXPORT_SYMBOL_GPL(close_candev);
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 6d0710d6f571d..a277d12332f15 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -22,6 +22,7 @@
 #include <linux/can/skb.h>
 #include <linux/ethtool.h>
 #include <linux/netdevice.h>
+#include <linux/workqueue.h>
 
 /*
  * CAN mode
@@ -115,6 +116,17 @@ struct can_priv *safe_candev_priv(struct net_device *dev);
 
 int open_candev(struct net_device *dev);
 void close_candev(struct net_device *dev);
+
+/* Cancel bus-off restart before tearing down resources used by the restart
+ * callback. The driver must still call close_candev() for the final cleanup.
+ */
+static inline void close_candev_cancel_restart_sync(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	cancel_delayed_work_sync(&priv->restart_work);
+}
+
 void can_set_default_mtu(struct net_device *dev);
 void can_set_cap_info(struct net_device *dev);
 int __must_check can_set_static_ctrlmode(struct net_device *dev,

-- 
2.34.1

[PATCH net v6 3/6] can: rockchip_canfd: cancel bus-off restart before closing the device

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The close path cancels restart_work in close_candev() only after freeing
the IRQ, disabling RX offload and stopping the controller. A concurrent
restart can re-enable the controller and interrupts after IRQ teardown,
or requeue timestamp work that accesses registers after runtime suspend
has disabled the controller clocks.

Call close_candev_cancel_restart_sync() at the start of ndo_stop(), while
the resources needed by a running restart are still available. Keep
close_candev() after IRQ teardown for final cancellation and echo cleanup.

During restart, mask the device's interrupts and drain active handlers
without disabling the shared IRQ line. Suspend handler access to the
controller until reinitialization is complete, and publish the initialized
state before resuming IRQ handling.

Drain timestamp work before reinitializing the timecounter, and initialize
the delayed work once at probe. Keep asynchronous cancellation in the
bus-off path. Also disable RX offload if request_irq() fails during open.

Fixes: ff60bfbaf67f ("can: rockchip_canfd: add driver for Rockchip CAN-FD controller")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v3:
- Replace disable_irq()/enable_irq() with device interrupt masking,
  mask readback, an irq_suspended flag and synchronize_irq().
- Pair release/acquire accesses to publish reinitialized state before
  the IRQ handler resumes, without disabling other shared IRQ users.
- Initialize timestamp delayed work once at probe and synchronously
  cancel it before reinitializing the timestamp state during restart.
- Disable RX offload when request_irq() fails during open.
---
 drivers/net/can/rockchip/rockchip_canfd-core.c      | 20 ++++++++++++++++++++
 drivers/net/can/rockchip/rockchip_canfd-timestamp.c |  6 +++++-
 drivers/net/can/rockchip/rockchip_canfd.h           |  2 ++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 37c1c22c40c9f..4b3db07242395 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -20,6 +20,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/smp.h>
 #include <linux/string.h>
 
 #include "rockchip_canfd.h"
@@ -356,7 +357,18 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 
 	switch (mode) {
 	case CAN_MODE_START:
+		rkcanfd_chip_interrupts_disable(priv);
+		/* Flush the interrupt mask write before suspending the handler. */
+		rkcanfd_read(priv, RKCANFD_REG_INT_MASK);
+		/* Keep shared IRQs from accessing the device during restart. */
+		WRITE_ONCE(priv->irq_suspended, true);
+		/* Wait for handlers that already passed the suspended check. */
+		synchronize_irq(ndev->irq);
+		rkcanfd_timestamp_stop_sync(priv);
+
 		rkcanfd_chip_start(priv);
+		/* Publish the initialized state before resuming IRQ handling. */
+		smp_store_release(&priv->irq_suspended, false);
 		rkcanfd_chip_interrupts_enable(priv);
 		netif_wake_queue(ndev);
 		break;
@@ -666,6 +678,10 @@ static irqreturn_t rkcanfd_irq(int irq, void *dev_id)
 	struct rkcanfd_priv *priv = dev_id;
 	u32 reg_int_unmasked, reg_int;
 
+	/* Pairs with the release after restart has initialized the device. */
+	if (smp_load_acquire(&priv->irq_suspended))
+		return IRQ_NONE;
+
 	reg_int_unmasked = rkcanfd_read(priv, RKCANFD_REG_INT);
 	reg_int = reg_int_unmasked & ~priv->reg_int_mask_default;
 
@@ -747,6 +763,7 @@ static int rkcanfd_open(struct net_device *ndev)
 	return 0;
 
 out_rkcanfd_chip_stop:
+	can_rx_offload_disable(&priv->offload);
 	rkcanfd_chip_stop_sync(priv, CAN_STATE_STOPPED);
 	pm_runtime_put(ndev->dev.parent);
 out_close_candev:
@@ -758,6 +775,7 @@ static int rkcanfd_stop(struct net_device *ndev)
 {
 	struct rkcanfd_priv *priv = netdev_priv(ndev);
 
+	close_candev_cancel_restart_sync(ndev);
 	netif_stop_queue(ndev);
 
 	rkcanfd_chip_interrupts_disable(priv);
@@ -934,6 +952,8 @@ static int rkcanfd_probe(struct platform_device *pdev)
 	if (err)
 		goto out_free_candev;
 
+	rkcanfd_timestamp_work_init(priv);
+
 	err = rkcanfd_register(priv);
 	if (err)
 		goto out_can_rx_offload_del;
diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index 72774cd2f94b7..ad582afbbd682 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -37,6 +37,11 @@ static void rkcanfd_timestamp_work(struct work_struct *work)
 	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
 }
 
+void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv)
+{
+	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
+}
+
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 {
 	const struct can_bittiming *dbt = &priv->can.fd.data_bittiming;
@@ -73,7 +78,6 @@ void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 	max_cycles = min(max_cycles, cc->mask);
 	work_delay_ns = clocksource_cyc2ns(max_cycles, cc->mult, cc->shift);
 	priv->work_delay_jiffies = div_u64(work_delay_ns, 3u * NSEC_PER_SEC / HZ);
-	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
 
 	netdev_dbg(priv->ndev, "clock=%lu.%02luMHz bitrate=%lu.%02luMBit/s div=%u rate=%lu.%02luMHz mult=%u shift=%u delay=%lus\n",
 		   priv->can.clock.freq / MEGA,
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 95bea9bfd8a2f..e1debab54534e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -480,6 +480,7 @@ struct rkcanfd_priv {
 
 	u32 reg_mode_default;
 	u32 reg_int_mask_default;
+	bool irq_suspended;
 	struct rkcanfd_devtype_data devtype_data;
 
 	struct cyclecounter cc;
@@ -551,6 +552,7 @@ int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv);
 
 void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp);
+void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_start(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_stop(struct rkcanfd_priv *priv);

-- 
2.34.1

[PATCH net v6 3/6] can: rockchip_canfd: cancel bus-off restart before closing the device

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The close path cancels restart_work in close_candev() only after freeing
the IRQ, disabling RX offload and stopping the controller. A concurrent
restart can re-enable the controller and interrupts after IRQ teardown,
or requeue timestamp work that accesses registers after runtime suspend
has disabled the controller clocks.

Call close_candev_cancel_restart_sync() at the start of ndo_stop(), while
the resources needed by a running restart are still available. Keep
close_candev() after IRQ teardown for final cancellation and echo cleanup.

During restart, mask the device's interrupts and drain active handlers
without disabling the shared IRQ line. Suspend handler access to the
controller until reinitialization is complete, and publish the initialized
state before resuming IRQ handling.

Drain timestamp work before reinitializing the timecounter, and initialize
the delayed work once at probe. Keep asynchronous cancellation in the
bus-off path. Also disable RX offload if request_irq() fails during open.

Fixes: ff60bfbaf67f ("can: rockchip_canfd: add driver for Rockchip CAN-FD controller")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v3:
- Replace disable_irq()/enable_irq() with device interrupt masking,
  mask readback, an irq_suspended flag and synchronize_irq().
- Pair release/acquire accesses to publish reinitialized state before
  the IRQ handler resumes, without disabling other shared IRQ users.
- Initialize timestamp delayed work once at probe and synchronously
  cancel it before reinitializing the timestamp state during restart.
- Disable RX offload when request_irq() fails during open.
---
 drivers/net/can/rockchip/rockchip_canfd-core.c      | 20 ++++++++++++++++++++
 drivers/net/can/rockchip/rockchip_canfd-timestamp.c |  6 +++++-
 drivers/net/can/rockchip/rockchip_canfd.h           |  2 ++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 37c1c22c40c9f..4b3db07242395 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -20,6 +20,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/smp.h>
 #include <linux/string.h>
 
 #include "rockchip_canfd.h"
@@ -356,7 +357,18 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 
 	switch (mode) {
 	case CAN_MODE_START:
+		rkcanfd_chip_interrupts_disable(priv);
+		/* Flush the interrupt mask write before suspending the handler. */
+		rkcanfd_read(priv, RKCANFD_REG_INT_MASK);
+		/* Keep shared IRQs from accessing the device during restart. */
+		WRITE_ONCE(priv->irq_suspended, true);
+		/* Wait for handlers that already passed the suspended check. */
+		synchronize_irq(ndev->irq);
+		rkcanfd_timestamp_stop_sync(priv);
+
 		rkcanfd_chip_start(priv);
+		/* Publish the initialized state before resuming IRQ handling. */
+		smp_store_release(&priv->irq_suspended, false);
 		rkcanfd_chip_interrupts_enable(priv);
 		netif_wake_queue(ndev);
 		break;
@@ -666,6 +678,10 @@ static irqreturn_t rkcanfd_irq(int irq, void *dev_id)
 	struct rkcanfd_priv *priv = dev_id;
 	u32 reg_int_unmasked, reg_int;
 
+	/* Pairs with the release after restart has initialized the device. */
+	if (smp_load_acquire(&priv->irq_suspended))
+		return IRQ_NONE;
+
 	reg_int_unmasked = rkcanfd_read(priv, RKCANFD_REG_INT);
 	reg_int = reg_int_unmasked & ~priv->reg_int_mask_default;
 
@@ -747,6 +763,7 @@ static int rkcanfd_open(struct net_device *ndev)
 	return 0;
 
 out_rkcanfd_chip_stop:
+	can_rx_offload_disable(&priv->offload);
 	rkcanfd_chip_stop_sync(priv, CAN_STATE_STOPPED);
 	pm_runtime_put(ndev->dev.parent);
 out_close_candev:
@@ -758,6 +775,7 @@ static int rkcanfd_stop(struct net_device *ndev)
 {
 	struct rkcanfd_priv *priv = netdev_priv(ndev);
 
+	close_candev_cancel_restart_sync(ndev);
 	netif_stop_queue(ndev);
 
 	rkcanfd_chip_interrupts_disable(priv);
@@ -934,6 +952,8 @@ static int rkcanfd_probe(struct platform_device *pdev)
 	if (err)
 		goto out_free_candev;
 
+	rkcanfd_timestamp_work_init(priv);
+
 	err = rkcanfd_register(priv);
 	if (err)
 		goto out_can_rx_offload_del;
diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index 72774cd2f94b7..ad582afbbd682 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -37,6 +37,11 @@ static void rkcanfd_timestamp_work(struct work_struct *work)
 	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
 }
 
+void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv)
+{
+	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
+}
+
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 {
 	const struct can_bittiming *dbt = &priv->can.fd.data_bittiming;
@@ -73,7 +78,6 @@ void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 	max_cycles = min(max_cycles, cc->mask);
 	work_delay_ns = clocksource_cyc2ns(max_cycles, cc->mult, cc->shift);
 	priv->work_delay_jiffies = div_u64(work_delay_ns, 3u * NSEC_PER_SEC / HZ);
-	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
 
 	netdev_dbg(priv->ndev, "clock=%lu.%02luMHz bitrate=%lu.%02luMBit/s div=%u rate=%lu.%02luMHz mult=%u shift=%u delay=%lus\n",
 		   priv->can.clock.freq / MEGA,
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 95bea9bfd8a2f..e1debab54534e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -480,6 +480,7 @@ struct rkcanfd_priv {
 
 	u32 reg_mode_default;
 	u32 reg_int_mask_default;
+	bool irq_suspended;
 	struct rkcanfd_devtype_data devtype_data;
 
 	struct cyclecounter cc;
@@ -551,6 +552,7 @@ int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv);
 
 void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp);
+void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_start(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_stop(struct rkcanfd_priv *priv);

-- 
2.34.1



_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

[PATCH net v6 3/6] can: rockchip_canfd: cancel bus-off restart before closing the device

[Cunhao Lu]

The close path cancels restart_work in close_candev() only after freeing
the IRQ, disabling RX offload and stopping the controller. A concurrent
restart can re-enable the controller and interrupts after IRQ teardown,
or requeue timestamp work that accesses registers after runtime suspend
has disabled the controller clocks.

Call close_candev_cancel_restart_sync() at the start of ndo_stop(), while
the resources needed by a running restart are still available. Keep
close_candev() after IRQ teardown for final cancellation and echo cleanup.

During restart, mask the device's interrupts and drain active handlers
without disabling the shared IRQ line. Suspend handler access to the
controller until reinitialization is complete, and publish the initialized
state before resuming IRQ handling.

Drain timestamp work before reinitializing the timecounter, and initialize
the delayed work once at probe. Keep asynchronous cancellation in the
bus-off path. Also disable RX offload if request_irq() fails during open.

Fixes: ff60bfbaf67f ("can: rockchip_canfd: add driver for Rockchip CAN-FD controller")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v3:
- Replace disable_irq()/enable_irq() with device interrupt masking,
  mask readback, an irq_suspended flag and synchronize_irq().
- Pair release/acquire accesses to publish reinitialized state before
  the IRQ handler resumes, without disabling other shared IRQ users.
- Initialize timestamp delayed work once at probe and synchronously
  cancel it before reinitializing the timestamp state during restart.
- Disable RX offload when request_irq() fails during open.
---
 drivers/net/can/rockchip/rockchip_canfd-core.c      | 20 ++++++++++++++++++++
 drivers/net/can/rockchip/rockchip_canfd-timestamp.c |  6 +++++-
 drivers/net/can/rockchip/rockchip_canfd.h           |  2 ++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 37c1c22c40c9f..4b3db07242395 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -20,6 +20,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/smp.h>
 #include <linux/string.h>
 
 #include "rockchip_canfd.h"
@@ -356,7 +357,18 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 
 	switch (mode) {
 	case CAN_MODE_START:
+		rkcanfd_chip_interrupts_disable(priv);
+		/* Flush the interrupt mask write before suspending the handler. */
+		rkcanfd_read(priv, RKCANFD_REG_INT_MASK);
+		/* Keep shared IRQs from accessing the device during restart. */
+		WRITE_ONCE(priv->irq_suspended, true);
+		/* Wait for handlers that already passed the suspended check. */
+		synchronize_irq(ndev->irq);
+		rkcanfd_timestamp_stop_sync(priv);
+
 		rkcanfd_chip_start(priv);
+		/* Publish the initialized state before resuming IRQ handling. */
+		smp_store_release(&priv->irq_suspended, false);
 		rkcanfd_chip_interrupts_enable(priv);
 		netif_wake_queue(ndev);
 		break;
@@ -666,6 +678,10 @@ static irqreturn_t rkcanfd_irq(int irq, void *dev_id)
 	struct rkcanfd_priv *priv = dev_id;
 	u32 reg_int_unmasked, reg_int;
 
+	/* Pairs with the release after restart has initialized the device. */
+	if (smp_load_acquire(&priv->irq_suspended))
+		return IRQ_NONE;
+
 	reg_int_unmasked = rkcanfd_read(priv, RKCANFD_REG_INT);
 	reg_int = reg_int_unmasked & ~priv->reg_int_mask_default;
 
@@ -747,6 +763,7 @@ static int rkcanfd_open(struct net_device *ndev)
 	return 0;
 
 out_rkcanfd_chip_stop:
+	can_rx_offload_disable(&priv->offload);
 	rkcanfd_chip_stop_sync(priv, CAN_STATE_STOPPED);
 	pm_runtime_put(ndev->dev.parent);
 out_close_candev:
@@ -758,6 +775,7 @@ static int rkcanfd_stop(struct net_device *ndev)
 {
 	struct rkcanfd_priv *priv = netdev_priv(ndev);
 
+	close_candev_cancel_restart_sync(ndev);
 	netif_stop_queue(ndev);
 
 	rkcanfd_chip_interrupts_disable(priv);
@@ -934,6 +952,8 @@ static int rkcanfd_probe(struct platform_device *pdev)
 	if (err)
 		goto out_free_candev;
 
+	rkcanfd_timestamp_work_init(priv);
+
 	err = rkcanfd_register(priv);
 	if (err)
 		goto out_can_rx_offload_del;
diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index 72774cd2f94b7..ad582afbbd682 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -37,6 +37,11 @@ static void rkcanfd_timestamp_work(struct work_struct *work)
 	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
 }
 
+void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv)
+{
+	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
+}
+
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 {
 	const struct can_bittiming *dbt = &priv->can.fd.data_bittiming;
@@ -73,7 +78,6 @@ void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 	max_cycles = min(max_cycles, cc->mask);
 	work_delay_ns = clocksource_cyc2ns(max_cycles, cc->mult, cc->shift);
 	priv->work_delay_jiffies = div_u64(work_delay_ns, 3u * NSEC_PER_SEC / HZ);
-	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
 
 	netdev_dbg(priv->ndev, "clock=%lu.%02luMHz bitrate=%lu.%02luMBit/s div=%u rate=%lu.%02luMHz mult=%u shift=%u delay=%lus\n",
 		   priv->can.clock.freq / MEGA,
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 95bea9bfd8a2f..e1debab54534e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -480,6 +480,7 @@ struct rkcanfd_priv {
 
 	u32 reg_mode_default;
 	u32 reg_int_mask_default;
+	bool irq_suspended;
 	struct rkcanfd_devtype_data devtype_data;
 
 	struct cyclecounter cc;
@@ -551,6 +552,7 @@ int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv);
 
 void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp);
+void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_start(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_stop(struct rkcanfd_priv *priv);

-- 
2.34.1

[PATCH net v6 4/6] can: rockchip_canfd: prevent timestamp work from rearming after bus-off

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The bus-off IRQ cancels timestamp work asynchronously. If the worker
is already running, it can requeue itself after cancellation and keep
polling while the controller remains bus-off.

Add a dedicated lock and an active flag, initialized once at probe.
Serialize the worker's active check, counter read and self-requeue with
start and stop. Clear the flag under the lock before cancelling work
so no worker can read the counter or rearm after deactivation. Enable
the flag and schedule the initial work under the same lock at start.

Keep both cancellation calls outside the lock so synchronous stop can
wait for the worker to finish.

Fixes: 4e1a18bab124 ("can: rockchip_canfd: add hardware timestamping support")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>
---
 .../net/can/rockchip/rockchip_canfd-timestamp.c    | 34 +++++++++++++++++++---
 drivers/net/can/rockchip/rockchip_canfd.h          |  4 +++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index ad582afbbd68..0fa791849c95 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -30,18 +30,27 @@ static void rkcanfd_timestamp_work(struct work_struct *work)
 {
 	const struct delayed_work *delayed_work = to_delayed_work(work);
 	struct rkcanfd_priv *priv;
+	unsigned long flags;
 
 	priv = container_of(delayed_work, struct rkcanfd_priv, timestamp);
-	timecounter_read(&priv->tc);
-
-	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	if (priv->timestamp_active) {
+		timecounter_read(&priv->tc);
+
+		/* Serialize requeueing with timestamp_stop(). */
+		schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	}
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 }
 
 void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv)
 {
+	spin_lock_init(&priv->timestamp_lock);
+	priv->timestamp_active = false;
 	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
 }
 
+/* The caller must quiesce IRQs and timestamp work before reconfiguration. */
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 {
 	const struct can_bittiming *dbt = &priv->can.fd.data_bittiming;
@@ -93,17 +102,34 @@ void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 
 void rkcanfd_timestamp_start(struct rkcanfd_priv *priv)
 {
-	timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
+	unsigned long flags;
 
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
+	priv->timestamp_active = true;
 	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 }
 
 void rkcanfd_timestamp_stop(struct rkcanfd_priv *priv)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	priv->timestamp_active = false;
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
+
 	cancel_delayed_work(&priv->timestamp);
 }
 
 void rkcanfd_timestamp_stop_sync(struct rkcanfd_priv *priv)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	priv->timestamp_active = false;
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
+
+	/* The worker needs timestamp_lock to finish. */
 	cancel_delayed_work_sync(&priv->timestamp);
 }
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index e1debab54534..2743c96ed42f 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -15,6 +15,7 @@
 #include <linux/netdevice.h>
 #include <linux/reset.h>
 #include <linux/skbuff.h>
+#include <linux/spinlock.h>
 #include <linux/timecounter.h>
 #include <linux/types.h>
 #include <linux/u64_stats_sync.h>
@@ -485,8 +486,11 @@ struct rkcanfd_priv {
 
 	struct cyclecounter cc;
 	struct timecounter tc;
+	/* Protects timestamp_active and worker reads/requeueing. */
+	spinlock_t timestamp_lock;
 	struct delayed_work timestamp;
 	unsigned long work_delay_jiffies;
+	bool timestamp_active;
 
 	struct can_berr_counter bec;
 

-- 
2.34.1

[PATCH net v6 4/6] can: rockchip_canfd: prevent timestamp work from rearming after bus-off

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The bus-off IRQ cancels timestamp work asynchronously. If the worker
is already running, it can requeue itself after cancellation and keep
polling while the controller remains bus-off.

Add a dedicated lock and an active flag, initialized once at probe.
Serialize the worker's active check, counter read and self-requeue with
start and stop. Clear the flag under the lock before cancelling work
so no worker can read the counter or rearm after deactivation. Enable
the flag and schedule the initial work under the same lock at start.

Keep both cancellation calls outside the lock so synchronous stop can
wait for the worker to finish.

Fixes: 4e1a18bab124 ("can: rockchip_canfd: add hardware timestamping support")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>
---
 .../net/can/rockchip/rockchip_canfd-timestamp.c    | 34 +++++++++++++++++++---
 drivers/net/can/rockchip/rockchip_canfd.h          |  4 +++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index ad582afbbd68..0fa791849c95 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -30,18 +30,27 @@ static void rkcanfd_timestamp_work(struct work_struct *work)
 {
 	const struct delayed_work *delayed_work = to_delayed_work(work);
 	struct rkcanfd_priv *priv;
+	unsigned long flags;
 
 	priv = container_of(delayed_work, struct rkcanfd_priv, timestamp);
-	timecounter_read(&priv->tc);
-
-	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	if (priv->timestamp_active) {
+		timecounter_read(&priv->tc);
+
+		/* Serialize requeueing with timestamp_stop(). */
+		schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	}
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 }
 
 void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv)
 {
+	spin_lock_init(&priv->timestamp_lock);
+	priv->timestamp_active = false;
 	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
 }
 
+/* The caller must quiesce IRQs and timestamp work before reconfiguration. */
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 {
 	const struct can_bittiming *dbt = &priv->can.fd.data_bittiming;
@@ -93,17 +102,34 @@ void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 
 void rkcanfd_timestamp_start(struct rkcanfd_priv *priv)
 {
-	timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
+	unsigned long flags;
 
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
+	priv->timestamp_active = true;
 	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 }
 
 void rkcanfd_timestamp_stop(struct rkcanfd_priv *priv)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	priv->timestamp_active = false;
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
+
 	cancel_delayed_work(&priv->timestamp);
 }
 
 void rkcanfd_timestamp_stop_sync(struct rkcanfd_priv *priv)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	priv->timestamp_active = false;
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
+
+	/* The worker needs timestamp_lock to finish. */
 	cancel_delayed_work_sync(&priv->timestamp);
 }
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index e1debab54534..2743c96ed42f 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -15,6 +15,7 @@
 #include <linux/netdevice.h>
 #include <linux/reset.h>
 #include <linux/skbuff.h>
+#include <linux/spinlock.h>
 #include <linux/timecounter.h>
 #include <linux/types.h>
 #include <linux/u64_stats_sync.h>
@@ -485,8 +486,11 @@ struct rkcanfd_priv {
 
 	struct cyclecounter cc;
 	struct timecounter tc;
+	/* Protects timestamp_active and worker reads/requeueing. */
+	spinlock_t timestamp_lock;
 	struct delayed_work timestamp;
 	unsigned long work_delay_jiffies;
+	bool timestamp_active;
 
 	struct can_berr_counter bec;
 

-- 
2.34.1



_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

[PATCH net v6 4/6] can: rockchip_canfd: prevent timestamp work from rearming after bus-off

[Cunhao Lu]

The bus-off IRQ cancels timestamp work asynchronously. If the worker
is already running, it can requeue itself after cancellation and keep
polling while the controller remains bus-off.

Add a dedicated lock and an active flag, initialized once at probe.
Serialize the worker's active check, counter read and self-requeue with
start and stop. Clear the flag under the lock before cancelling work
so no worker can read the counter or rearm after deactivation. Enable
the flag and schedule the initial work under the same lock at start.

Keep both cancellation calls outside the lock so synchronous stop can
wait for the worker to finish.

Fixes: 4e1a18bab124 ("can: rockchip_canfd: add hardware timestamping support")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>
---
 .../net/can/rockchip/rockchip_canfd-timestamp.c    | 34 +++++++++++++++++++---
 drivers/net/can/rockchip/rockchip_canfd.h          |  4 +++
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index ad582afbbd68..0fa791849c95 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -30,18 +30,27 @@ static void rkcanfd_timestamp_work(struct work_struct *work)
 {
 	const struct delayed_work *delayed_work = to_delayed_work(work);
 	struct rkcanfd_priv *priv;
+	unsigned long flags;
 
 	priv = container_of(delayed_work, struct rkcanfd_priv, timestamp);
-	timecounter_read(&priv->tc);
-
-	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	if (priv->timestamp_active) {
+		timecounter_read(&priv->tc);
+
+		/* Serialize requeueing with timestamp_stop(). */
+		schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	}
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 }
 
 void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv)
 {
+	spin_lock_init(&priv->timestamp_lock);
+	priv->timestamp_active = false;
 	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
 }
 
+/* The caller must quiesce IRQs and timestamp work before reconfiguration. */
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 {
 	const struct can_bittiming *dbt = &priv->can.fd.data_bittiming;
@@ -93,17 +102,34 @@ void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 
 void rkcanfd_timestamp_start(struct rkcanfd_priv *priv)
 {
-	timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
+	unsigned long flags;
 
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	timecounter_init(&priv->tc, &priv->cc, ktime_get_real_ns());
+	priv->timestamp_active = true;
 	schedule_delayed_work(&priv->timestamp, priv->work_delay_jiffies);
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 }
 
 void rkcanfd_timestamp_stop(struct rkcanfd_priv *priv)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	priv->timestamp_active = false;
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
+
 	cancel_delayed_work(&priv->timestamp);
 }
 
 void rkcanfd_timestamp_stop_sync(struct rkcanfd_priv *priv)
 {
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
+	priv->timestamp_active = false;
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
+
+	/* The worker needs timestamp_lock to finish. */
 	cancel_delayed_work_sync(&priv->timestamp);
 }
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index e1debab54534..2743c96ed42f 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -15,6 +15,7 @@
 #include <linux/netdevice.h>
 #include <linux/reset.h>
 #include <linux/skbuff.h>
+#include <linux/spinlock.h>
 #include <linux/timecounter.h>
 #include <linux/types.h>
 #include <linux/u64_stats_sync.h>
@@ -485,8 +486,11 @@ struct rkcanfd_priv {
 
 	struct cyclecounter cc;
 	struct timecounter tc;
+	/* Protects timestamp_active and worker reads/requeueing. */
+	spinlock_t timestamp_lock;
 	struct delayed_work timestamp;
 	unsigned long work_delay_jiffies;
+	bool timestamp_active;
 
 	struct can_berr_counter bec;
 

-- 
2.34.1

[PATCH net v6 5/6] can: rockchip_canfd: serialize TX with bus-off and restart

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The bus-off path can reset the controller while ndo_start_xmit() is
active. CAN restart also flushes the echo ring before calling set_mode(),
so disabling TX in that callback is too late to protect echo slots.

Serialize TX submission, RX-side completion and retry with a private
lock and enabled flag. Disable TX and drain these users before publishing
CAN_STATE_BUS_OFF, protecting the core's echo flush during automatic and
manual recovery. Reject further submissions with NETDEV_TX_BUSY.

If close disables TX after an RX IRQ has consumed a self-transmitted
frame, skipping echo filtering alone would deliver it as ordinary RX.
Check tx_enabled under the same lock after consuming the FIFO entry. If
TX is disabled, drop the entry without accessing the echo ring, retrying
TX, waking the queue or allocating an ordinary RX skb. Return success so
the caller continues draining the FIFO.

After draining the old IRQ and reinitializing the controller, restore
carrier, enable TX, resume IRQ handling and wake the queue under the
lock. This prevents the old bus-off IRQ from leaving manual recovery
with carrier off, while allowing a new bus-off to take precedence.

Keep shared IRQ handling suspended during open until initialization is
complete, and leave TX disabled on close or failed open. Keep resets and
synchronous IRQ/work draining outside the lock.

Keep a reference to the original skb across can_put_echo_skb() and
release it after unlocking, so its socket destructor cannot run with
hard IRQs disabled. If echo preparation fails, drop the frame without
advancing tx_head, accounting BQL or requesting TX. This also fixes the
existing failure path that could stall TX on an empty echo slot.

Fixes: b6661d73290c ("can: rockchip_canfd: add TX PATH")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Defer the original skb's release until after unlocking.
- Abort TX submission if echo preparation fails.

Changes in v5:
- Drop consumed RX FIFO entries when tx_enabled is false under tx_lock,
  rather than skipping only echo filtering and delivering them as RX.
---
 drivers/net/can/rockchip/rockchip_canfd-core.c | 51 ++++++++++++++++++++++----
 drivers/net/can/rockchip/rockchip_canfd-rx.c   | 26 +++++++++----
 drivers/net/can/rockchip/rockchip_canfd-tx.c   | 40 +++++++++++++++++---
 drivers/net/can/rockchip/rockchip_canfd.h      |  3 ++
 4 files changed, 100 insertions(+), 20 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 4b3db07242395..150748c0b6845 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -326,6 +326,35 @@ static void rkcanfd_chip_start(struct rkcanfd_priv *priv)
 		   rkcanfd_read(priv, RKCANFD_REG_MODE));
 }
 
+static void rkcanfd_tx_disable(struct rkcanfd_priv *priv)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	priv->tx_enabled = false;
+	netif_stop_queue(priv->ndev);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+}
+
+static void rkcanfd_chip_start_finish(struct rkcanfd_priv *priv)
+{
+	unsigned long flags;
+
+	/* Serialize carrier, IRQ enable and queue wake with a new bus-off. */
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	/* A manual restart may have raced with the old bus-off IRQ's
+	 * netif_carrier_off(). That IRQ is now drained; restore carrier
+	 * before resuming IRQ handling so a new bus-off takes precedence.
+	 */
+	netif_carrier_on(priv->ndev);
+	priv->tx_enabled = true;
+	/* Publish the initialized state before resuming IRQ handling. */
+	smp_store_release(&priv->irq_suspended, false);
+	rkcanfd_chip_interrupts_enable(priv);
+	netif_wake_queue(priv->ndev);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+}
+
 static void __rkcanfd_chip_stop(struct rkcanfd_priv *priv, const enum can_state state)
 {
 	priv->can.state = state;
@@ -357,6 +386,7 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 
 	switch (mode) {
 	case CAN_MODE_START:
+		rkcanfd_tx_disable(priv);
 		rkcanfd_chip_interrupts_disable(priv);
 		/* Flush the interrupt mask write before suspending the handler. */
 		rkcanfd_read(priv, RKCANFD_REG_INT_MASK);
@@ -367,10 +397,7 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 		rkcanfd_timestamp_stop_sync(priv);
 
 		rkcanfd_chip_start(priv);
-		/* Publish the initialized state before resuming IRQ handling. */
-		smp_store_release(&priv->irq_suspended, false);
-		rkcanfd_chip_interrupts_enable(priv);
-		netif_wake_queue(ndev);
+		rkcanfd_chip_start_finish(priv);
 		break;
 
 	default:
@@ -604,6 +631,12 @@ static int rkcanfd_handle_state_error_int(struct rkcanfd_priv *priv)
 	 * handles cf == NULL.
 	 */
 	skb = rkcanfd_alloc_can_err_skb(priv, &cf, &timestamp);
+	if (new_state == CAN_STATE_BUS_OFF) {
+		/* Drain TX before publishing BUS_OFF, which permits a manual
+		 * restart to flush echo SKBs before calling our set_mode().
+		 */
+		rkcanfd_tx_disable(priv);
+	}
 	can_change_state(ndev, cf, tx_state, rx_state);
 
 	if (new_state == CAN_STATE_BUS_OFF) {
@@ -749,6 +782,8 @@ static int rkcanfd_open(struct net_device *ndev)
 	if (err)
 		goto out_close_candev;
 
+	/* A shared IRQ may run as soon as request_irq() succeeds. */
+	WRITE_ONCE(priv->irq_suspended, true);
 	rkcanfd_chip_start(priv);
 	can_rx_offload_enable(&priv->offload);
 
@@ -756,13 +791,12 @@ static int rkcanfd_open(struct net_device *ndev)
 	if (err)
 		goto out_rkcanfd_chip_stop;
 
-	rkcanfd_chip_interrupts_enable(priv);
-
-	netif_start_queue(ndev);
+	rkcanfd_chip_start_finish(priv);
 
 	return 0;
 
 out_rkcanfd_chip_stop:
+	rkcanfd_tx_disable(priv);
 	can_rx_offload_disable(&priv->offload);
 	rkcanfd_chip_stop_sync(priv, CAN_STATE_STOPPED);
 	pm_runtime_put(ndev->dev.parent);
@@ -776,7 +810,7 @@ static int rkcanfd_stop(struct net_device *ndev)
 	struct rkcanfd_priv *priv = netdev_priv(ndev);
 
 	close_candev_cancel_restart_sync(ndev);
-	netif_stop_queue(ndev);
+	rkcanfd_tx_disable(priv);
 
 	rkcanfd_chip_interrupts_disable(priv);
 	free_irq(ndev->irq, priv);
@@ -939,6 +973,7 @@ static int rkcanfd_probe(struct platform_device *pdev)
 	priv->can.do_set_mode = rkcanfd_set_mode;
 	priv->can.do_get_berr_counter = rkcanfd_get_berr_counter;
 	priv->ndev = ndev;
+	spin_lock_init(&priv->tx_lock);
 
 	match = device_get_match_data(&pdev->dev);
 	if (match) {
diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c
index 24e87daa1df00..5e64317d4eee6 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-rx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c
@@ -91,6 +91,7 @@ rkcanfd_fifo_header_to_cfd_header(const struct rkcanfd_priv *priv,
 	return len + cfd->len;
 }
 
+/* Called with tx_lock held and TX enabled. */
 static int rkcanfd_rxstx_filter(struct rkcanfd_priv *priv,
 				const struct canfd_frame *cfd_rx, const u32 ts,
 				bool *tx_done)
@@ -204,7 +205,9 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv)
 	struct canfd_frame cfd[1] = { }, *skb_cfd;
 	struct rkcanfd_fifo_header header[1] = { };
 	struct sk_buff *skb;
+	unsigned long flags;
 	unsigned int len;
+	bool tx_done = false;
 	int err;
 
 	/* read header into separate struct and convert it later */
@@ -237,15 +240,24 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv)
 		return 0;
 	}
 
-	if (rkcanfd_get_tx_pending(priv)) {
-		bool tx_done = false;
+	/* Drop FIFO entries while TX is disabled, as they may be self-
+	 * received frames. Do not access the echo ring, retry TX or wake the
+	 * queue while restart owns the ring. The entry is already consumed.
+	 */
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	if (unlikely(!priv->tx_enabled)) {
+		spin_unlock_irqrestore(&priv->tx_lock, flags);
+		return 0;
+	}
 
+	err = 0;
+	if (rkcanfd_get_tx_pending(priv))
 		err = rkcanfd_rxstx_filter(priv, cfd, header->ts, &tx_done);
-		if (err)
-			return err;
-		if (tx_done && !(priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK))
-			return 0;
-	}
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	if (err)
+		return err;
+	if (tx_done && !(priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK))
+		return 0;
 
 	/* Manual handling of CAN Bus Error counters. See
 	 * rkcanfd_get_corrected_berr_counter() for detailed
diff --git a/drivers/net/can/rockchip/rockchip_canfd-tx.c b/drivers/net/can/rockchip/rockchip_canfd-tx.c
index 12200dcfd3389..f86e31599b0a8 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-tx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-tx.c
@@ -69,12 +69,19 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	u32 reg_frameinfo, reg_id, reg_cmd;
 	unsigned int tx_head, frame_len;
 	const struct canfd_frame *cfd;
+	unsigned long flags;
 	int err;
 	u8 i;
 
 	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	if (unlikely(!priv->tx_enabled)) {
+		netif_stop_queue(ndev);
+		goto out_busy;
+	}
+
 	if (!netif_subqueue_maybe_stop(priv->ndev, 0,
 				       rkcanfd_get_effective_tx_free(priv),
 				       RKCANFD_TX_STOP_THRESHOLD,
@@ -85,7 +92,7 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 				    priv->tx_head, priv->tx_tail,
 				    rkcanfd_get_tx_pending(priv));
 
-		return NETDEV_TX_BUSY;
+		goto out_busy;
 	}
 
 	cfd = (struct canfd_frame *)skb->data;
@@ -117,16 +124,21 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	tx_head = rkcanfd_get_tx_head(priv);
 	reg_cmd = RKCANFD_REG_CMD_TX_REQ(tx_head);
 
+	/* Keep the original skb alive until IRQs are restored so echo
+	 * preparation cannot invoke its socket destructor under tx_lock.
+	 */
+	frame_len = can_skb_get_frame_len(skb);
+	err = can_put_echo_skb(skb_get(skb), ndev, tx_head, frame_len);
+	if (unlikely(err || !priv->can.echo_skb[tx_head]))
+		goto out_drop;
+
 	rkcanfd_write(priv, RKCANFD_REG_FD_TXFRAMEINFO, reg_frameinfo);
 	rkcanfd_write(priv, RKCANFD_REG_FD_TXID, reg_id);
 	for (i = 0; i < cfd->len; i += 4)
 		rkcanfd_write(priv, RKCANFD_REG_FD_TXDATA0 + i,
 			      *(u32 *)(cfd->data + i));
 
-	frame_len = can_skb_get_frame_len(skb);
-	err = can_put_echo_skb(skb, ndev, tx_head, frame_len);
-	if (!err)
-		netdev_sent_queue(priv->ndev, frame_len);
+	netdev_sent_queue(priv->ndev, frame_len);
 
 	WRITE_ONCE(priv->tx_head, priv->tx_head + 1);
 
@@ -137,7 +149,25 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 				  RKCANFD_TX_STOP_THRESHOLD,
 				  RKCANFD_TX_START_THRESHOLD);
 
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	dev_consume_skb_any(skb);
+
+	return NETDEV_TX_OK;
+
+out_drop:
+	ndev->stats.tx_dropped++;
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	/* An invalid index leaves the extra reference unconsumed. */
+	if (err == -EINVAL)
+		dev_kfree_skb_any(skb);
+	dev_kfree_skb_any(skb);
+
 	return NETDEV_TX_OK;
+
+out_busy:
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+
+	return NETDEV_TX_BUSY;
 }
 
 void rkcanfd_handle_tx_done_one(struct rkcanfd_priv *priv, const u32 ts,
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 2743c96ed42f0..4a2bdc205296e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -476,6 +476,9 @@ struct rkcanfd_priv {
 	struct net_device *ndev;
 
 	void __iomem *regs;
+	/* Serialize TX submission/completion with bus-off and restart. */
+	spinlock_t tx_lock;
+	bool tx_enabled;
 	unsigned int tx_head;
 	unsigned int tx_tail;
 

-- 
2.34.1

[PATCH net v6 5/6] can: rockchip_canfd: serialize TX with bus-off and restart

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The bus-off path can reset the controller while ndo_start_xmit() is
active. CAN restart also flushes the echo ring before calling set_mode(),
so disabling TX in that callback is too late to protect echo slots.

Serialize TX submission, RX-side completion and retry with a private
lock and enabled flag. Disable TX and drain these users before publishing
CAN_STATE_BUS_OFF, protecting the core's echo flush during automatic and
manual recovery. Reject further submissions with NETDEV_TX_BUSY.

If close disables TX after an RX IRQ has consumed a self-transmitted
frame, skipping echo filtering alone would deliver it as ordinary RX.
Check tx_enabled under the same lock after consuming the FIFO entry. If
TX is disabled, drop the entry without accessing the echo ring, retrying
TX, waking the queue or allocating an ordinary RX skb. Return success so
the caller continues draining the FIFO.

After draining the old IRQ and reinitializing the controller, restore
carrier, enable TX, resume IRQ handling and wake the queue under the
lock. This prevents the old bus-off IRQ from leaving manual recovery
with carrier off, while allowing a new bus-off to take precedence.

Keep shared IRQ handling suspended during open until initialization is
complete, and leave TX disabled on close or failed open. Keep resets and
synchronous IRQ/work draining outside the lock.

Keep a reference to the original skb across can_put_echo_skb() and
release it after unlocking, so its socket destructor cannot run with
hard IRQs disabled. If echo preparation fails, drop the frame without
advancing tx_head, accounting BQL or requesting TX. This also fixes the
existing failure path that could stall TX on an empty echo slot.

Fixes: b6661d73290c ("can: rockchip_canfd: add TX PATH")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Defer the original skb's release until after unlocking.
- Abort TX submission if echo preparation fails.

Changes in v5:
- Drop consumed RX FIFO entries when tx_enabled is false under tx_lock,
  rather than skipping only echo filtering and delivering them as RX.
---
 drivers/net/can/rockchip/rockchip_canfd-core.c | 51 ++++++++++++++++++++++----
 drivers/net/can/rockchip/rockchip_canfd-rx.c   | 26 +++++++++----
 drivers/net/can/rockchip/rockchip_canfd-tx.c   | 40 +++++++++++++++++---
 drivers/net/can/rockchip/rockchip_canfd.h      |  3 ++
 4 files changed, 100 insertions(+), 20 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 4b3db07242395..150748c0b6845 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -326,6 +326,35 @@ static void rkcanfd_chip_start(struct rkcanfd_priv *priv)
 		   rkcanfd_read(priv, RKCANFD_REG_MODE));
 }
 
+static void rkcanfd_tx_disable(struct rkcanfd_priv *priv)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	priv->tx_enabled = false;
+	netif_stop_queue(priv->ndev);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+}
+
+static void rkcanfd_chip_start_finish(struct rkcanfd_priv *priv)
+{
+	unsigned long flags;
+
+	/* Serialize carrier, IRQ enable and queue wake with a new bus-off. */
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	/* A manual restart may have raced with the old bus-off IRQ's
+	 * netif_carrier_off(). That IRQ is now drained; restore carrier
+	 * before resuming IRQ handling so a new bus-off takes precedence.
+	 */
+	netif_carrier_on(priv->ndev);
+	priv->tx_enabled = true;
+	/* Publish the initialized state before resuming IRQ handling. */
+	smp_store_release(&priv->irq_suspended, false);
+	rkcanfd_chip_interrupts_enable(priv);
+	netif_wake_queue(priv->ndev);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+}
+
 static void __rkcanfd_chip_stop(struct rkcanfd_priv *priv, const enum can_state state)
 {
 	priv->can.state = state;
@@ -357,6 +386,7 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 
 	switch (mode) {
 	case CAN_MODE_START:
+		rkcanfd_tx_disable(priv);
 		rkcanfd_chip_interrupts_disable(priv);
 		/* Flush the interrupt mask write before suspending the handler. */
 		rkcanfd_read(priv, RKCANFD_REG_INT_MASK);
@@ -367,10 +397,7 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 		rkcanfd_timestamp_stop_sync(priv);
 
 		rkcanfd_chip_start(priv);
-		/* Publish the initialized state before resuming IRQ handling. */
-		smp_store_release(&priv->irq_suspended, false);
-		rkcanfd_chip_interrupts_enable(priv);
-		netif_wake_queue(ndev);
+		rkcanfd_chip_start_finish(priv);
 		break;
 
 	default:
@@ -604,6 +631,12 @@ static int rkcanfd_handle_state_error_int(struct rkcanfd_priv *priv)
 	 * handles cf == NULL.
 	 */
 	skb = rkcanfd_alloc_can_err_skb(priv, &cf, &timestamp);
+	if (new_state == CAN_STATE_BUS_OFF) {
+		/* Drain TX before publishing BUS_OFF, which permits a manual
+		 * restart to flush echo SKBs before calling our set_mode().
+		 */
+		rkcanfd_tx_disable(priv);
+	}
 	can_change_state(ndev, cf, tx_state, rx_state);
 
 	if (new_state == CAN_STATE_BUS_OFF) {
@@ -749,6 +782,8 @@ static int rkcanfd_open(struct net_device *ndev)
 	if (err)
 		goto out_close_candev;
 
+	/* A shared IRQ may run as soon as request_irq() succeeds. */
+	WRITE_ONCE(priv->irq_suspended, true);
 	rkcanfd_chip_start(priv);
 	can_rx_offload_enable(&priv->offload);
 
@@ -756,13 +791,12 @@ static int rkcanfd_open(struct net_device *ndev)
 	if (err)
 		goto out_rkcanfd_chip_stop;
 
-	rkcanfd_chip_interrupts_enable(priv);
-
-	netif_start_queue(ndev);
+	rkcanfd_chip_start_finish(priv);
 
 	return 0;
 
 out_rkcanfd_chip_stop:
+	rkcanfd_tx_disable(priv);
 	can_rx_offload_disable(&priv->offload);
 	rkcanfd_chip_stop_sync(priv, CAN_STATE_STOPPED);
 	pm_runtime_put(ndev->dev.parent);
@@ -776,7 +810,7 @@ static int rkcanfd_stop(struct net_device *ndev)
 	struct rkcanfd_priv *priv = netdev_priv(ndev);
 
 	close_candev_cancel_restart_sync(ndev);
-	netif_stop_queue(ndev);
+	rkcanfd_tx_disable(priv);
 
 	rkcanfd_chip_interrupts_disable(priv);
 	free_irq(ndev->irq, priv);
@@ -939,6 +973,7 @@ static int rkcanfd_probe(struct platform_device *pdev)
 	priv->can.do_set_mode = rkcanfd_set_mode;
 	priv->can.do_get_berr_counter = rkcanfd_get_berr_counter;
 	priv->ndev = ndev;
+	spin_lock_init(&priv->tx_lock);
 
 	match = device_get_match_data(&pdev->dev);
 	if (match) {
diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c
index 24e87daa1df00..5e64317d4eee6 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-rx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c
@@ -91,6 +91,7 @@ rkcanfd_fifo_header_to_cfd_header(const struct rkcanfd_priv *priv,
 	return len + cfd->len;
 }
 
+/* Called with tx_lock held and TX enabled. */
 static int rkcanfd_rxstx_filter(struct rkcanfd_priv *priv,
 				const struct canfd_frame *cfd_rx, const u32 ts,
 				bool *tx_done)
@@ -204,7 +205,9 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv)
 	struct canfd_frame cfd[1] = { }, *skb_cfd;
 	struct rkcanfd_fifo_header header[1] = { };
 	struct sk_buff *skb;
+	unsigned long flags;
 	unsigned int len;
+	bool tx_done = false;
 	int err;
 
 	/* read header into separate struct and convert it later */
@@ -237,15 +240,24 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv)
 		return 0;
 	}
 
-	if (rkcanfd_get_tx_pending(priv)) {
-		bool tx_done = false;
+	/* Drop FIFO entries while TX is disabled, as they may be self-
+	 * received frames. Do not access the echo ring, retry TX or wake the
+	 * queue while restart owns the ring. The entry is already consumed.
+	 */
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	if (unlikely(!priv->tx_enabled)) {
+		spin_unlock_irqrestore(&priv->tx_lock, flags);
+		return 0;
+	}
 
+	err = 0;
+	if (rkcanfd_get_tx_pending(priv))
 		err = rkcanfd_rxstx_filter(priv, cfd, header->ts, &tx_done);
-		if (err)
-			return err;
-		if (tx_done && !(priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK))
-			return 0;
-	}
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	if (err)
+		return err;
+	if (tx_done && !(priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK))
+		return 0;
 
 	/* Manual handling of CAN Bus Error counters. See
 	 * rkcanfd_get_corrected_berr_counter() for detailed
diff --git a/drivers/net/can/rockchip/rockchip_canfd-tx.c b/drivers/net/can/rockchip/rockchip_canfd-tx.c
index 12200dcfd3389..f86e31599b0a8 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-tx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-tx.c
@@ -69,12 +69,19 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	u32 reg_frameinfo, reg_id, reg_cmd;
 	unsigned int tx_head, frame_len;
 	const struct canfd_frame *cfd;
+	unsigned long flags;
 	int err;
 	u8 i;
 
 	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	if (unlikely(!priv->tx_enabled)) {
+		netif_stop_queue(ndev);
+		goto out_busy;
+	}
+
 	if (!netif_subqueue_maybe_stop(priv->ndev, 0,
 				       rkcanfd_get_effective_tx_free(priv),
 				       RKCANFD_TX_STOP_THRESHOLD,
@@ -85,7 +92,7 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 				    priv->tx_head, priv->tx_tail,
 				    rkcanfd_get_tx_pending(priv));
 
-		return NETDEV_TX_BUSY;
+		goto out_busy;
 	}
 
 	cfd = (struct canfd_frame *)skb->data;
@@ -117,16 +124,21 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	tx_head = rkcanfd_get_tx_head(priv);
 	reg_cmd = RKCANFD_REG_CMD_TX_REQ(tx_head);
 
+	/* Keep the original skb alive until IRQs are restored so echo
+	 * preparation cannot invoke its socket destructor under tx_lock.
+	 */
+	frame_len = can_skb_get_frame_len(skb);
+	err = can_put_echo_skb(skb_get(skb), ndev, tx_head, frame_len);
+	if (unlikely(err || !priv->can.echo_skb[tx_head]))
+		goto out_drop;
+
 	rkcanfd_write(priv, RKCANFD_REG_FD_TXFRAMEINFO, reg_frameinfo);
 	rkcanfd_write(priv, RKCANFD_REG_FD_TXID, reg_id);
 	for (i = 0; i < cfd->len; i += 4)
 		rkcanfd_write(priv, RKCANFD_REG_FD_TXDATA0 + i,
 			      *(u32 *)(cfd->data + i));
 
-	frame_len = can_skb_get_frame_len(skb);
-	err = can_put_echo_skb(skb, ndev, tx_head, frame_len);
-	if (!err)
-		netdev_sent_queue(priv->ndev, frame_len);
+	netdev_sent_queue(priv->ndev, frame_len);
 
 	WRITE_ONCE(priv->tx_head, priv->tx_head + 1);
 
@@ -137,7 +149,25 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 				  RKCANFD_TX_STOP_THRESHOLD,
 				  RKCANFD_TX_START_THRESHOLD);
 
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	dev_consume_skb_any(skb);
+
+	return NETDEV_TX_OK;
+
+out_drop:
+	ndev->stats.tx_dropped++;
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	/* An invalid index leaves the extra reference unconsumed. */
+	if (err == -EINVAL)
+		dev_kfree_skb_any(skb);
+	dev_kfree_skb_any(skb);
+
 	return NETDEV_TX_OK;
+
+out_busy:
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+
+	return NETDEV_TX_BUSY;
 }
 
 void rkcanfd_handle_tx_done_one(struct rkcanfd_priv *priv, const u32 ts,
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 2743c96ed42f0..4a2bdc205296e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -476,6 +476,9 @@ struct rkcanfd_priv {
 	struct net_device *ndev;
 
 	void __iomem *regs;
+	/* Serialize TX submission/completion with bus-off and restart. */
+	spinlock_t tx_lock;
+	bool tx_enabled;
 	unsigned int tx_head;
 	unsigned int tx_tail;
 

-- 
2.34.1



_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

[PATCH net v6 5/6] can: rockchip_canfd: serialize TX with bus-off and restart

[Cunhao Lu]

The bus-off path can reset the controller while ndo_start_xmit() is
active. CAN restart also flushes the echo ring before calling set_mode(),
so disabling TX in that callback is too late to protect echo slots.

Serialize TX submission, RX-side completion and retry with a private
lock and enabled flag. Disable TX and drain these users before publishing
CAN_STATE_BUS_OFF, protecting the core's echo flush during automatic and
manual recovery. Reject further submissions with NETDEV_TX_BUSY.

If close disables TX after an RX IRQ has consumed a self-transmitted
frame, skipping echo filtering alone would deliver it as ordinary RX.
Check tx_enabled under the same lock after consuming the FIFO entry. If
TX is disabled, drop the entry without accessing the echo ring, retrying
TX, waking the queue or allocating an ordinary RX skb. Return success so
the caller continues draining the FIFO.

After draining the old IRQ and reinitializing the controller, restore
carrier, enable TX, resume IRQ handling and wake the queue under the
lock. This prevents the old bus-off IRQ from leaving manual recovery
with carrier off, while allowing a new bus-off to take precedence.

Keep shared IRQ handling suspended during open until initialization is
complete, and leave TX disabled on close or failed open. Keep resets and
synchronous IRQ/work draining outside the lock.

Keep a reference to the original skb across can_put_echo_skb() and
release it after unlocking, so its socket destructor cannot run with
hard IRQs disabled. If echo preparation fails, drop the frame without
advancing tx_head, accounting BQL or requesting TX. This also fixes the
existing failure path that could stall TX on an empty echo slot.

Fixes: b6661d73290c ("can: rockchip_canfd: add TX PATH")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>

---
Changes in v6:
- Defer the original skb's release until after unlocking.
- Abort TX submission if echo preparation fails.

Changes in v5:
- Drop consumed RX FIFO entries when tx_enabled is false under tx_lock,
  rather than skipping only echo filtering and delivering them as RX.
---
 drivers/net/can/rockchip/rockchip_canfd-core.c | 51 ++++++++++++++++++++++----
 drivers/net/can/rockchip/rockchip_canfd-rx.c   | 26 +++++++++----
 drivers/net/can/rockchip/rockchip_canfd-tx.c   | 40 +++++++++++++++++---
 drivers/net/can/rockchip/rockchip_canfd.h      |  3 ++
 4 files changed, 100 insertions(+), 20 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 4b3db07242395..150748c0b6845 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -326,6 +326,35 @@ static void rkcanfd_chip_start(struct rkcanfd_priv *priv)
 		   rkcanfd_read(priv, RKCANFD_REG_MODE));
 }
 
+static void rkcanfd_tx_disable(struct rkcanfd_priv *priv)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	priv->tx_enabled = false;
+	netif_stop_queue(priv->ndev);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+}
+
+static void rkcanfd_chip_start_finish(struct rkcanfd_priv *priv)
+{
+	unsigned long flags;
+
+	/* Serialize carrier, IRQ enable and queue wake with a new bus-off. */
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	/* A manual restart may have raced with the old bus-off IRQ's
+	 * netif_carrier_off(). That IRQ is now drained; restore carrier
+	 * before resuming IRQ handling so a new bus-off takes precedence.
+	 */
+	netif_carrier_on(priv->ndev);
+	priv->tx_enabled = true;
+	/* Publish the initialized state before resuming IRQ handling. */
+	smp_store_release(&priv->irq_suspended, false);
+	rkcanfd_chip_interrupts_enable(priv);
+	netif_wake_queue(priv->ndev);
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+}
+
 static void __rkcanfd_chip_stop(struct rkcanfd_priv *priv, const enum can_state state)
 {
 	priv->can.state = state;
@@ -357,6 +386,7 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 
 	switch (mode) {
 	case CAN_MODE_START:
+		rkcanfd_tx_disable(priv);
 		rkcanfd_chip_interrupts_disable(priv);
 		/* Flush the interrupt mask write before suspending the handler. */
 		rkcanfd_read(priv, RKCANFD_REG_INT_MASK);
@@ -367,10 +397,7 @@ static int rkcanfd_set_mode(struct net_device *ndev,
 		rkcanfd_timestamp_stop_sync(priv);
 
 		rkcanfd_chip_start(priv);
-		/* Publish the initialized state before resuming IRQ handling. */
-		smp_store_release(&priv->irq_suspended, false);
-		rkcanfd_chip_interrupts_enable(priv);
-		netif_wake_queue(ndev);
+		rkcanfd_chip_start_finish(priv);
 		break;
 
 	default:
@@ -604,6 +631,12 @@ static int rkcanfd_handle_state_error_int(struct rkcanfd_priv *priv)
 	 * handles cf == NULL.
 	 */
 	skb = rkcanfd_alloc_can_err_skb(priv, &cf, &timestamp);
+	if (new_state == CAN_STATE_BUS_OFF) {
+		/* Drain TX before publishing BUS_OFF, which permits a manual
+		 * restart to flush echo SKBs before calling our set_mode().
+		 */
+		rkcanfd_tx_disable(priv);
+	}
 	can_change_state(ndev, cf, tx_state, rx_state);
 
 	if (new_state == CAN_STATE_BUS_OFF) {
@@ -749,6 +782,8 @@ static int rkcanfd_open(struct net_device *ndev)
 	if (err)
 		goto out_close_candev;
 
+	/* A shared IRQ may run as soon as request_irq() succeeds. */
+	WRITE_ONCE(priv->irq_suspended, true);
 	rkcanfd_chip_start(priv);
 	can_rx_offload_enable(&priv->offload);
 
@@ -756,13 +791,12 @@ static int rkcanfd_open(struct net_device *ndev)
 	if (err)
 		goto out_rkcanfd_chip_stop;
 
-	rkcanfd_chip_interrupts_enable(priv);
-
-	netif_start_queue(ndev);
+	rkcanfd_chip_start_finish(priv);
 
 	return 0;
 
 out_rkcanfd_chip_stop:
+	rkcanfd_tx_disable(priv);
 	can_rx_offload_disable(&priv->offload);
 	rkcanfd_chip_stop_sync(priv, CAN_STATE_STOPPED);
 	pm_runtime_put(ndev->dev.parent);
@@ -776,7 +810,7 @@ static int rkcanfd_stop(struct net_device *ndev)
 	struct rkcanfd_priv *priv = netdev_priv(ndev);
 
 	close_candev_cancel_restart_sync(ndev);
-	netif_stop_queue(ndev);
+	rkcanfd_tx_disable(priv);
 
 	rkcanfd_chip_interrupts_disable(priv);
 	free_irq(ndev->irq, priv);
@@ -939,6 +973,7 @@ static int rkcanfd_probe(struct platform_device *pdev)
 	priv->can.do_set_mode = rkcanfd_set_mode;
 	priv->can.do_get_berr_counter = rkcanfd_get_berr_counter;
 	priv->ndev = ndev;
+	spin_lock_init(&priv->tx_lock);
 
 	match = device_get_match_data(&pdev->dev);
 	if (match) {
diff --git a/drivers/net/can/rockchip/rockchip_canfd-rx.c b/drivers/net/can/rockchip/rockchip_canfd-rx.c
index 24e87daa1df00..5e64317d4eee6 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-rx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-rx.c
@@ -91,6 +91,7 @@ rkcanfd_fifo_header_to_cfd_header(const struct rkcanfd_priv *priv,
 	return len + cfd->len;
 }
 
+/* Called with tx_lock held and TX enabled. */
 static int rkcanfd_rxstx_filter(struct rkcanfd_priv *priv,
 				const struct canfd_frame *cfd_rx, const u32 ts,
 				bool *tx_done)
@@ -204,7 +205,9 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv)
 	struct canfd_frame cfd[1] = { }, *skb_cfd;
 	struct rkcanfd_fifo_header header[1] = { };
 	struct sk_buff *skb;
+	unsigned long flags;
 	unsigned int len;
+	bool tx_done = false;
 	int err;
 
 	/* read header into separate struct and convert it later */
@@ -237,15 +240,24 @@ static int rkcanfd_handle_rx_int_one(struct rkcanfd_priv *priv)
 		return 0;
 	}
 
-	if (rkcanfd_get_tx_pending(priv)) {
-		bool tx_done = false;
+	/* Drop FIFO entries while TX is disabled, as they may be self-
+	 * received frames. Do not access the echo ring, retry TX or wake the
+	 * queue while restart owns the ring. The entry is already consumed.
+	 */
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	if (unlikely(!priv->tx_enabled)) {
+		spin_unlock_irqrestore(&priv->tx_lock, flags);
+		return 0;
+	}
 
+	err = 0;
+	if (rkcanfd_get_tx_pending(priv))
 		err = rkcanfd_rxstx_filter(priv, cfd, header->ts, &tx_done);
-		if (err)
-			return err;
-		if (tx_done && !(priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK))
-			return 0;
-	}
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	if (err)
+		return err;
+	if (tx_done && !(priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK))
+		return 0;
 
 	/* Manual handling of CAN Bus Error counters. See
 	 * rkcanfd_get_corrected_berr_counter() for detailed
diff --git a/drivers/net/can/rockchip/rockchip_canfd-tx.c b/drivers/net/can/rockchip/rockchip_canfd-tx.c
index 12200dcfd3389..f86e31599b0a8 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-tx.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-tx.c
@@ -69,12 +69,19 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	u32 reg_frameinfo, reg_id, reg_cmd;
 	unsigned int tx_head, frame_len;
 	const struct canfd_frame *cfd;
+	unsigned long flags;
 	int err;
 	u8 i;
 
 	if (can_dev_dropped_skb(ndev, skb))
 		return NETDEV_TX_OK;
 
+	spin_lock_irqsave(&priv->tx_lock, flags);
+	if (unlikely(!priv->tx_enabled)) {
+		netif_stop_queue(ndev);
+		goto out_busy;
+	}
+
 	if (!netif_subqueue_maybe_stop(priv->ndev, 0,
 				       rkcanfd_get_effective_tx_free(priv),
 				       RKCANFD_TX_STOP_THRESHOLD,
@@ -85,7 +92,7 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 				    priv->tx_head, priv->tx_tail,
 				    rkcanfd_get_tx_pending(priv));
 
-		return NETDEV_TX_BUSY;
+		goto out_busy;
 	}
 
 	cfd = (struct canfd_frame *)skb->data;
@@ -117,16 +124,21 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	tx_head = rkcanfd_get_tx_head(priv);
 	reg_cmd = RKCANFD_REG_CMD_TX_REQ(tx_head);
 
+	/* Keep the original skb alive until IRQs are restored so echo
+	 * preparation cannot invoke its socket destructor under tx_lock.
+	 */
+	frame_len = can_skb_get_frame_len(skb);
+	err = can_put_echo_skb(skb_get(skb), ndev, tx_head, frame_len);
+	if (unlikely(err || !priv->can.echo_skb[tx_head]))
+		goto out_drop;
+
 	rkcanfd_write(priv, RKCANFD_REG_FD_TXFRAMEINFO, reg_frameinfo);
 	rkcanfd_write(priv, RKCANFD_REG_FD_TXID, reg_id);
 	for (i = 0; i < cfd->len; i += 4)
 		rkcanfd_write(priv, RKCANFD_REG_FD_TXDATA0 + i,
 			      *(u32 *)(cfd->data + i));
 
-	frame_len = can_skb_get_frame_len(skb);
-	err = can_put_echo_skb(skb, ndev, tx_head, frame_len);
-	if (!err)
-		netdev_sent_queue(priv->ndev, frame_len);
+	netdev_sent_queue(priv->ndev, frame_len);
 
 	WRITE_ONCE(priv->tx_head, priv->tx_head + 1);
 
@@ -137,7 +149,25 @@ netdev_tx_t rkcanfd_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 				  RKCANFD_TX_STOP_THRESHOLD,
 				  RKCANFD_TX_START_THRESHOLD);
 
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	dev_consume_skb_any(skb);
+
+	return NETDEV_TX_OK;
+
+out_drop:
+	ndev->stats.tx_dropped++;
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+	/* An invalid index leaves the extra reference unconsumed. */
+	if (err == -EINVAL)
+		dev_kfree_skb_any(skb);
+	dev_kfree_skb_any(skb);
+
 	return NETDEV_TX_OK;
+
+out_busy:
+	spin_unlock_irqrestore(&priv->tx_lock, flags);
+
+	return NETDEV_TX_BUSY;
 }
 
 void rkcanfd_handle_tx_done_one(struct rkcanfd_priv *priv, const u32 ts,
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 2743c96ed42f0..4a2bdc205296e 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -476,6 +476,9 @@ struct rkcanfd_priv {
 	struct net_device *ndev;
 
 	void __iomem *regs;
+	/* Serialize TX submission/completion with bus-off and restart. */
+	spinlock_t tx_lock;
+	bool tx_enabled;
 	unsigned int tx_head;
 	unsigned int tx_tail;
 

-- 
2.34.1

[PATCH net v6 6/6] can: rockchip_canfd: serialize timecounter timestamp conversion

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The timestamp worker advances the timecounter with timecounter_read()
while RX, TX completion and error-frame paths use timecounter_cyc2time()
to convert hardware timestamps without holding timestamp_lock.

timecounter_read() updates frac, cycle_last and nsec in separate steps.
A concurrent conversion can observe the new cycle_last with the old
nsec and produce an incorrect timestamp.

Hold timestamp_lock across timecounter_cyc2time(), using the same lock
as timecounter_read() and timecounter_init(). Keep the SKB timestamp
assignment outside the critical section.

TX completion nests timestamp_lock inside tx_lock; no timestamp-lock
holder acquires tx_lock.

Fixes: 4e1a18bab124 ("can: rockchip_canfd: add hardware timestamping support")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>
---
 drivers/net/can/rockchip/rockchip_canfd-timestamp.c | 5 ++++-
 drivers/net/can/rockchip/rockchip_canfd.h           | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index 0fa791849c95..05f1005ee506 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -15,13 +15,16 @@ static u64 rkcanfd_timestamp_read(struct cyclecounter *cc)
 	return rkcanfd_get_timestamp(priv);
 }
 
-void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
+void rkcanfd_skb_set_timestamp(struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp)
 {
 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
+	unsigned long flags;
 	u64 ns;
 
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
 	ns = timecounter_cyc2time(&priv->tc, timestamp);
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 
 	hwtstamps->hwtstamp = ns_to_ktime(ns);
 }
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 4a2bdc205296..63f146ff8e6b 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -489,7 +489,7 @@ struct rkcanfd_priv {
 
 	struct cyclecounter cc;
 	struct timecounter tc;
-	/* Protects timestamp_active and worker reads/requeueing. */
+	/* Protects tc, timestamp_active and worker requeueing. */
 	spinlock_t timestamp_lock;
 	struct delayed_work timestamp;
 	unsigned long work_delay_jiffies;
@@ -557,7 +557,7 @@ void rkcanfd_ethtool_init(struct rkcanfd_priv *priv);
 
 int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv);
 
-void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
+void rkcanfd_skb_set_timestamp(struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp);
 void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv);

-- 
2.34.1

[PATCH net v6 6/6] can: rockchip_canfd: serialize timecounter timestamp conversion

[Cunhao Lu via B4 Relay]

From: Cunhao Lu <1579567540@qq.com>

The timestamp worker advances the timecounter with timecounter_read()
while RX, TX completion and error-frame paths use timecounter_cyc2time()
to convert hardware timestamps without holding timestamp_lock.

timecounter_read() updates frac, cycle_last and nsec in separate steps.
A concurrent conversion can observe the new cycle_last with the old
nsec and produce an incorrect timestamp.

Hold timestamp_lock across timecounter_cyc2time(), using the same lock
as timecounter_read() and timecounter_init(). Keep the SKB timestamp
assignment outside the critical section.

TX completion nests timestamp_lock inside tx_lock; no timestamp-lock
holder acquires tx_lock.

Fixes: 4e1a18bab124 ("can: rockchip_canfd: add hardware timestamping support")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>
---
 drivers/net/can/rockchip/rockchip_canfd-timestamp.c | 5 ++++-
 drivers/net/can/rockchip/rockchip_canfd.h           | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index 0fa791849c95..05f1005ee506 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -15,13 +15,16 @@ static u64 rkcanfd_timestamp_read(struct cyclecounter *cc)
 	return rkcanfd_get_timestamp(priv);
 }
 
-void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
+void rkcanfd_skb_set_timestamp(struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp)
 {
 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
+	unsigned long flags;
 	u64 ns;
 
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
 	ns = timecounter_cyc2time(&priv->tc, timestamp);
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 
 	hwtstamps->hwtstamp = ns_to_ktime(ns);
 }
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 4a2bdc205296..63f146ff8e6b 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -489,7 +489,7 @@ struct rkcanfd_priv {
 
 	struct cyclecounter cc;
 	struct timecounter tc;
-	/* Protects timestamp_active and worker reads/requeueing. */
+	/* Protects tc, timestamp_active and worker requeueing. */
 	spinlock_t timestamp_lock;
 	struct delayed_work timestamp;
 	unsigned long work_delay_jiffies;
@@ -557,7 +557,7 @@ void rkcanfd_ethtool_init(struct rkcanfd_priv *priv);
 
 int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv);
 
-void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
+void rkcanfd_skb_set_timestamp(struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp);
 void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv);

-- 
2.34.1



_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

[PATCH net v6 6/6] can: rockchip_canfd: serialize timecounter timestamp conversion

[Cunhao Lu]

The timestamp worker advances the timecounter with timecounter_read()
while RX, TX completion and error-frame paths use timecounter_cyc2time()
to convert hardware timestamps without holding timestamp_lock.

timecounter_read() updates frac, cycle_last and nsec in separate steps.
A concurrent conversion can observe the new cycle_last with the old
nsec and produce an incorrect timestamp.

Hold timestamp_lock across timecounter_cyc2time(), using the same lock
as timecounter_read() and timecounter_init(). Keep the SKB timestamp
assignment outside the critical section.

TX completion nests timestamp_lock inside tx_lock; no timestamp-lock
holder acquires tx_lock.

Fixes: 4e1a18bab124 ("can: rockchip_canfd: add hardware timestamping support")
Cc: stable@vger.kernel.org
Signed-off-by: Cunhao Lu <1579567540@qq.com>
---
 drivers/net/can/rockchip/rockchip_canfd-timestamp.c | 5 ++++-
 drivers/net/can/rockchip/rockchip_canfd.h           | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
index 0fa791849c95..05f1005ee506 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-timestamp.c
@@ -15,13 +15,16 @@ static u64 rkcanfd_timestamp_read(struct cyclecounter *cc)
 	return rkcanfd_get_timestamp(priv);
 }
 
-void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
+void rkcanfd_skb_set_timestamp(struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp)
 {
 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
+	unsigned long flags;
 	u64 ns;
 
+	spin_lock_irqsave(&priv->timestamp_lock, flags);
 	ns = timecounter_cyc2time(&priv->tc, timestamp);
+	spin_unlock_irqrestore(&priv->timestamp_lock, flags);
 
 	hwtstamps->hwtstamp = ns_to_ktime(ns);
 }
diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
index 4a2bdc205296..63f146ff8e6b 100644
--- a/drivers/net/can/rockchip/rockchip_canfd.h
+++ b/drivers/net/can/rockchip/rockchip_canfd.h
@@ -489,7 +489,7 @@ struct rkcanfd_priv {
 
 	struct cyclecounter cc;
 	struct timecounter tc;
-	/* Protects timestamp_active and worker reads/requeueing. */
+	/* Protects tc, timestamp_active and worker requeueing. */
 	spinlock_t timestamp_lock;
 	struct delayed_work timestamp;
 	unsigned long work_delay_jiffies;
@@ -557,7 +557,7 @@ void rkcanfd_ethtool_init(struct rkcanfd_priv *priv);
 
 int rkcanfd_handle_rx_int(struct rkcanfd_priv *priv);
 
-void rkcanfd_skb_set_timestamp(const struct rkcanfd_priv *priv,
+void rkcanfd_skb_set_timestamp(struct rkcanfd_priv *priv,
 			       struct sk_buff *skb, const u32 timestamp);
 void rkcanfd_timestamp_work_init(struct rkcanfd_priv *priv);
 void rkcanfd_timestamp_init(struct rkcanfd_priv *priv);

-- 
2.34.1

Re: [PATCH net v6 3/6] can: rockchip_canfd: cancel bus-off restart before closing the device

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] can: rockchip_canfd: ad-hoc flag synchronization in rkcanfd_set_mode()
--

commit 84108d981e4356f8149159f043033d7bbecd5e53
Author: Cunhao Lu <1579567540@qq.com>

can: rockchip_canfd: cancel bus-off restart before closing the device

This commit cancels bus-off restart work at the beginning of ndo_stop(),
synchronizes interrupt and timestamp handling across controller restart in
rkcanfd_set_mode(), and disables RX offload on request_irq() failure in
rkcanfd_open().

> diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
> index 37c1c22c40c9f..4b3db07242395 100644
> --- a/drivers/net/can/rockchip/rockchip_canfd-core.c
> +++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
[ ... ]
> @@ -356,7 +357,18 @@ static int rkcanfd_set_mode(struct net_device *ndev,
>  
>  	switch (mode) {
>  	case CAN_MODE_START:
> +		rkcanfd_chip_interrupts_disable(priv);
> +		/* Flush the interrupt mask write before suspending the handler. */
> +		rkcanfd_read(priv, RKCANFD_REG_INT_MASK);
> +		/* Keep shared IRQs from accessing the device during restart. */
> +		WRITE_ONCE(priv->irq_suspended, true);
> +		/* Wait for handlers that already passed the suspended check. */
> +		synchronize_irq(ndev->irq);
> +		rkcanfd_timestamp_stop_sync(priv);
> +
>  		rkcanfd_chip_start(priv);
> +		/* Publish the initialized state before resuming IRQ handling. */
> +		smp_store_release(&priv->irq_suspended, false);
>  		rkcanfd_chip_interrupts_enable(priv);
>  		netif_wake_queue(ndev);
>  		break;
> @@ -666,6 +678,10 @@ static irqreturn_t rkcanfd_irq(int irq, void *dev_id)
>  	struct rkcanfd_priv *priv = dev_id;
>  	u32 reg_int_unmasked, reg_int;
>  
> +	/* Pairs with the release after restart has initialized the device. */
> +	if (smp_load_acquire(&priv->irq_suspended))
> +		return IRQ_NONE;
> +
>  	reg_int_unmasked = rkcanfd_read(priv, RKCANFD_REG_INT);
>  	reg_int = reg_int_unmasked & ~priv->reg_int_mask_default;

[Severity: Medium]
Does using priv->irq_suspended as a boolean gate flag between
rkcanfd_set_mode() and rkcanfd_irq() leave a race window during controller
restart and shared IRQ handling?

Setting priv->irq_suspended on entry to rkcanfd_set_mode() and clearing it on
exit acts as an ad-hoc lock that is invisible to lockdep and does not
serialize against other concurrent readers or writers of shared state (such as
rkcanfd_get_berr_counter()).

In addition, rkcanfd_chip_start() already puts the controller into
RKCANFD_REG_MODE_WORK_MODE and sets priv->can.state = CAN_STATE_ERROR_ACTIVE
before rkcanfd_set_mode() clears priv->irq_suspended:

can_restart()
  rkcanfd_set_mode(ndev, CAN_MODE_START)
    rkcanfd_chip_start(priv)
      rkcanfd_chip_set_work_mode(priv);
      priv->can.state = CAN_STATE_ERROR_ACTIVE;
    smp_store_release(&priv->irq_suspended, false);
    rkcanfd_chip_interrupts_enable(priv);
    netif_wake_queue(ndev);

Because rkcanfd_irq() reads the raw unmasked interrupt status from
RKCANFD_REG_INT and masks it in software with ~priv->reg_int_mask_default
rather than consulting RKCANFD_REG_INT_MASK, a shared IRQ firing on the
IRQF_SHARED line after smp_store_release(&priv->irq_suspended, false) (or an
interrupt firing right as rkcanfd_chip_interrupts_enable() unmasks hardware
interrupts) can enter rkcanfd_irq() and handle a new bus-off condition before
rkcanfd_set_mode() finishes:

rkcanfd_irq()
  rkcanfd_handle_state_error_int()
    rkcanfd_chip_stop(priv, CAN_STATE_BUS_OFF)
    can_bus_off(ndev)

When rkcanfd_set_mode() then executes rkcanfd_chip_interrupts_enable(priv) and
netif_wake_queue(ndev), wouldn't it unmask interrupts on the stopped
controller and wake the transmit queue while priv->can.state is
CAN_STATE_BUS_OFF?

Similarly, because rkcanfd_irq() only checks priv->irq_suspended (which is
only set during rkcanfd_set_mode()) and masks RKCANFD_REG_INT with
~priv->reg_int_mask_default, shared IRQs arriving during rkcanfd_open()
between request_irq() and rkcanfd_chip_interrupts_enable(), or while in
CAN_STATE_BUS_OFF after rkcanfd_chip_stop() masks RKCANFD_REG_INT_MASK, can
still evaluate pending bits in RKCANFD_REG_INT. Would a proper spinlock (or
honoring the active mask state under a lock) avoid this race?

[ ... ]

> diff --git a/drivers/net/can/rockchip/rockchip_canfd.h b/drivers/net/can/rockchip/rockchip_canfd.h
> index 95bea9bfd8a2f..e1debab54534e 100644
> --- a/drivers/net/can/rockchip/rockchip_canfd.h
> +++ b/drivers/net/can/rockchip/rockchip_canfd.h
> @@ -480,6 +480,7 @@ struct rkcanfd_priv {
>  
>  	u32 reg_mode_default;
>  	u32 reg_int_mask_default;
> +	bool irq_suspended;
>  	struct rkcanfd_devtype_data devtype_data;
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261017-rockchip-canfd-restart-close-v6-0-ed605feb4b6e@qq.com?part=3

Re: [PATCH net v6 3/6] can: rockchip_canfd: cancel bus-off restart before closing the device

[Cunhao Lu]

Hi,

> [Severity: Medium]
> Does using priv->irq_suspended as a boolean gate flag between
> rkcanfd_set_mode() and rkcanfd_irq() leave a race window during controller
> restart and shared IRQ handling?

The flag works together with synchronize_irq() to keep the IRQ handler
from accessing the device during reinitialization. synchronize_irq()
waits for handlers that have already passed the flag check.

> Setting priv->irq_suspended on entry to rkcanfd_set_mode() and clearing it on
> exit acts as an ad-hoc lock that is invisible to lockdep and does not
> serialize against other concurrent readers or writers of shared state (such as
> rkcanfd_get_berr_counter()).

The BEC cache race is a pre-existing issue. I will leave it out of this
series for now. When I have time, I will send a separate patch to fix it.

> In addition, rkcanfd_chip_start() already puts the controller into
> RKCANFD_REG_MODE_WORK_MODE and sets priv->can.state = CAN_STATE_ERROR_ACTIVE
> before rkcanfd_set_mode() clears priv->irq_suspended:
>
> can_restart()
>   rkcanfd_set_mode(ndev, CAN_MODE_START)
>     rkcanfd_chip_start(priv)
>       rkcanfd_chip_set_work_mode(priv);
>       priv->can.state = CAN_STATE_ERROR_ACTIVE;
>     smp_store_release(&priv->irq_suspended, false);
>     rkcanfd_chip_interrupts_enable(priv);
>     netif_wake_queue(ndev);
>
> Because rkcanfd_irq() reads the raw unmasked interrupt status from
> RKCANFD_REG_INT and masks it in software with ~priv->reg_int_mask_default
> rather than consulting RKCANFD_REG_INT_MASK, a shared IRQ firing on the
> IRQF_SHARED line after smp_store_release(&priv->irq_suspended, false) (or an
> interrupt firing right as rkcanfd_chip_interrupts_enable() unmasks hardware
> interrupts) can enter rkcanfd_irq() and handle a new bus-off condition before
> rkcanfd_set_mode() finishes:
>
> rkcanfd_irq()
>   rkcanfd_handle_state_error_int()
>     rkcanfd_chip_stop(priv, CAN_STATE_BUS_OFF)
>     can_bus_off(ndev)
>
> When rkcanfd_set_mode() then executes rkcanfd_chip_interrupts_enable(priv) and
> netif_wake_queue(ndev), wouldn't it unmask interrupts on the stopped
> controller and wake the transmit queue while priv->can.state is
> CAN_STATE_BUS_OFF?

This is already handled by patch 5/6. rkcanfd_chip_start_finish() holds
tx_lock while clearing irq_suspended, enabling interrupts and waking
the queue. The bus-off path takes the same lock in rkcanfd_tx_disable()
before publishing BUS_OFF and stopping the controller. A new bus-off
therefore takes effect after startup finishes.

> Similarly, because rkcanfd_irq() only checks priv->irq_suspended (which is
> only set during rkcanfd_set_mode()) and masks RKCANFD_REG_INT with
> ~priv->reg_int_mask_default, shared IRQs arriving during rkcanfd_open()
> between request_irq() and rkcanfd_chip_interrupts_enable(), or while in
> CAN_STATE_BUS_OFF after rkcanfd_chip_stop() masks RKCANFD_REG_INT_MASK, can
> still evaluate pending bits in RKCANFD_REG_INT. Would a proper spinlock (or
> honoring the active mask state under a lock) avoid this race?

Patch 5/6 also sets irq_suspended in rkcanfd_open() before request_irq().
It is cleared in rkcanfd_chip_start_finish() under tx_lock.

The bus-off stop path already resets the hardware and clears WORK_MODE.
I have not observed a failure caused by pending bits remaining after
reset, so I do not think this should be considered a bug.

Regards,
Cunhao Lu