[RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Steven Rostedt]

Back in April, I posted an RFC patch set to help mitigate a common issue
where a timer gets armed just before it is freed, and when the timer
goes off, it crashes in the timer code without any evidence of who the
culprit was. I got side tracked and never finished up on that patch set.
Since this type of crash is still our #1 crash we are seeing in the field,
it has become a priority again to finish it.

This is v3 of that patch set. Thomas Gleixner posted an untested version
that makes timer->function NULL as the flag that it is shutdown. I took that
code, tested it (fixed it up), added more comments, and changed the
name to timer_shutdown_sync(). I also converted it to use WARN_ON_ONCE()
instead of just WARN_ON() as Linus asked for.

I then created a trivial coccinelle script to find where del_timer*()
is called before being freed, and converted them all to timer_shutdown*()
(There was a couple that still used del_timer() instead of del_timer_sync()).

I also updated DEBUG_OBJECTS_TIMERS to check from where the timer is ever
armed, to calling of timer_shutdown_sync(), and it will trigger if a timer
is freed in between. The current way is to only check if the timer is armed,
but that means it only triggers if the race condition is hit, and with
experience, it's not run on enough machines to catch all of them. By triggering
it from the time the timer is armed to the time it is shutdown, it catches
all potential cases even if the race condition is not hit.

I went though the result of the cocinelle script, and updated the locations.
Some locations were caught by DEBUG_OBJECTS_TIMERS as the coccinelle script
only checked for timers being freed in the same function as the del_timer*().

Ideally, I would have the first patch go into this rc cycle, which is mostly
non functional as it will allow the other patches to come in via the respective
subsystems in the next merge window.

Changes since v2: https://lore.kernel.org/all/20221027150525.753064657@goodmis.org/

 - Talking with Thomas Gleixner, he wanted a better name space and to remove
   the "del_" portion of the API.

 - Since there's now a shutdown interface that does not synchronize, to keep
   it closer to del_timer() and del_timer_sync(), the API is now:

    timer_shutdown() - same as del_timer() but deactivates the timer.

    timer_shutdown_sync() - same as del_timer_sync() but deactivates the timer.

 - Added a few more locations that got converted.

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace/timers

Head SHA1: 25106f0bb7968b3e8c746a7853f44b51840746c3


Steven Rostedt (Google) (33):
      timers: Add timer_shutdown_sync() and timer_shutdown() to be called before freeing timers
      timers: s390/cmm: Use timer_shutdown_sync() before freeing timer
      timers: sh: Use timer_shutdown_sync() before freeing timer
      timers: block: Use timer_shutdown_sync() before freeing timer
      timers: ACPI: Use timer_shutdown_sync() before freeing timer
      timers: atm: Use timer_shutdown_sync() before freeing timer
      timers: PM: Use timer_shutdown_sync()
      timers: Bluetooth: Use timer_shutdown_sync() before freeing timer
      timers: hangcheck: Use timer_shutdown_sync() before freeing timer
      timers: ipmi: Use timer_shutdown_sync() before freeing timer
      random: use timer_shutdown_sync() before freeing timer
      timers: dma-buf: Use timer_shutdown_sync() before freeing timer
      timers: drm: Use timer_shutdown_sync() before freeing timer
      timers: HID: Use timer_shutdown_sync() before freeing timer
      timers: Input: Use timer_shutdown_sync() before freeing timer
      timers: mISDN: Use timer_shutdown_sync() before freeing timer
      timers: leds: Use timer_shutdown_sync() before freeing timer
      timers: media: Use timer_shutdown_sync() before freeing timer
      timers: net: Use timer_shutdown_sync() before freeing timer
      timers: usb: Use timer_shutdown_sync() before freeing timer
      timers: cgroup: Use timer_shutdown_sync() before freeing timer
      timers: workqueue: Use timer_shutdown_sync() before freeing timer
      timers: nfc: pn533: Use timer_shutdown_sync() before freeing timer
      timers: pcmcia: Use timer_shutdown_sync() before freeing timer
      timers: scsi: Use timer_shutdown_sync() and timer_shutdown() before freeing timer
      timers: tty: Use timer_shutdown_sync() before freeing timer
      timers: ext4: Use timer_shutdown_sync() before freeing timer
      timers: fs/nilfs2: Use timer_shutdown_sync() before freeing timer
      timers: ALSA: Use timer_shutdown_sync() before freeing timer
      timers: jbd2: Use timer_shutdown() before freeing timer
      timers: sched/psi: Use timer_shutdown_sync() before freeing timer
      timers: x86/mce: Use __init_timer() for resetting timers
      timers: Expand DEBUG_OBJECTS_TIMER to check if it ever was used

----
 .../RCU/Design/Requirements/Requirements.rst       |   2 +-
 Documentation/core-api/local_ops.rst               |   2 +-
 Documentation/kernel-hacking/locking.rst           |   5 +
 arch/s390/mm/cmm.c                                 |   4 +-
 arch/sh/drivers/push-switch.c                      |   2 +-
 arch/x86/kernel/cpu/mce/core.c                     |  14 ++-
 block/blk-iocost.c                                 |   2 +-
 block/blk-iolatency.c                              |   2 +-
 block/blk-stat.c                                   |   2 +-
 block/blk-throttle.c                               |   2 +-
 block/kyber-iosched.c                              |   2 +-
 drivers/acpi/apei/ghes.c                           |   2 +-
 drivers/atm/idt77105.c                             |   4 +-
 drivers/atm/idt77252.c                             |   4 +-
 drivers/atm/iphase.c                               |   2 +-
 drivers/base/power/wakeup.c                        |   7 +-
 drivers/block/drbd/drbd_main.c                     |   2 +-
 drivers/block/loop.c                               |   2 +-
 drivers/block/sunvdc.c                             |   2 +-
 drivers/bluetooth/hci_bcsp.c                       |   2 +-
 drivers/bluetooth/hci_h5.c                         |   2 +-
 drivers/bluetooth/hci_qca.c                        |   4 +-
 drivers/char/hangcheck-timer.c                     |   4 +-
 drivers/char/ipmi/ipmi_msghandler.c                |   2 +-
 drivers/char/ipmi/ipmi_ssif.c                      |   4 +-
 drivers/char/random.c                              |   2 +-
 drivers/dma-buf/st-dma-fence.c                     |   2 +-
 drivers/gpu/drm/gud/gud_pipe.c                     |   2 +-
 drivers/gpu/drm/i915/i915_sw_fence.c               |   2 +-
 drivers/hid/hid-wiimote-core.c                     |   2 +-
 drivers/input/keyboard/locomokbd.c                 |   2 +-
 drivers/input/keyboard/omap-keypad.c               |   2 +-
 drivers/input/mouse/alps.c                         |   2 +-
 drivers/input/serio/hil_mlc.c                      |   2 +-
 drivers/input/serio/hp_sdc.c                       |   2 +-
 drivers/isdn/hardware/mISDN/hfcmulti.c             |   6 +-
 drivers/isdn/mISDN/l1oip_core.c                    |   4 +-
 drivers/isdn/mISDN/timerdev.c                      |   4 +-
 drivers/leds/trigger/ledtrig-activity.c            |   2 +-
 drivers/leds/trigger/ledtrig-heartbeat.c           |   2 +-
 drivers/leds/trigger/ledtrig-pattern.c             |   2 +-
 drivers/leds/trigger/ledtrig-transient.c           |   2 +-
 drivers/media/pci/ivtv/ivtv-driver.c               |   2 +-
 drivers/media/usb/pvrusb2/pvrusb2-hdw.c            |  18 ++--
 drivers/media/usb/s2255/s2255drv.c                 |   4 +-
 drivers/net/ethernet/intel/i40e/i40e_main.c        |   6 +-
 drivers/net/ethernet/marvell/sky2.c                |   2 +-
 drivers/net/ethernet/sun/sunvnet.c                 |   2 +-
 drivers/net/usb/sierra_net.c                       |   2 +-
 drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c   |   2 +-
 drivers/net/wireless/intersil/hostap/hostap_ap.c   |   2 +-
 drivers/net/wireless/marvell/mwifiex/main.c        |   2 +-
 drivers/net/wireless/microchip/wilc1000/hif.c      |   8 +-
 drivers/nfc/pn533/pn533.c                          |   2 +-
 drivers/nfc/pn533/uart.c                           |   2 +-
 drivers/pcmcia/bcm63xx_pcmcia.c                    |   2 +-
 drivers/pcmcia/electra_cf.c                        |   2 +-
 drivers/pcmcia/omap_cf.c                           |   2 +-
 drivers/pcmcia/pd6729.c                            |   4 +-
 drivers/pcmcia/yenta_socket.c                      |   4 +-
 drivers/scsi/qla2xxx/qla_edif.c                    |   4 +-
 drivers/scsi/scsi_lib.c                            |   1 +
 drivers/staging/media/atomisp/i2c/atomisp-lm3554.c |   2 +-
 drivers/tty/n_gsm.c                                |   2 +-
 drivers/tty/sysrq.c                                |   2 +-
 drivers/usb/gadget/udc/m66592-udc.c                |   2 +-
 drivers/usb/serial/garmin_gps.c                    |   2 +-
 drivers/usb/serial/mos7840.c                       |   2 +-
 fs/ext4/super.c                                    |   2 +-
 fs/jbd2/journal.c                                  |   2 +
 fs/nilfs2/segment.c                                |   2 +-
 include/linux/timer.h                              | 100 +++++++++++++++++--
 include/linux/workqueue.h                          |   4 +-
 kernel/cgroup/cgroup.c                             |   2 +-
 kernel/sched/psi.c                                 |   1 +
 kernel/time/timer.c                                | 106 ++++++++++++++-------
 kernel/workqueue.c                                 |   4 +-
 net/802/garp.c                                     |   2 +-
 net/802/mrp.c                                      |   2 +-
 net/bridge/br_multicast.c                          |   6 +-
 net/bridge/br_multicast_eht.c                      |   4 +-
 net/core/gen_estimator.c                           |   2 +-
 net/core/neighbour.c                               |   2 +
 net/ipv4/inet_connection_sock.c                    |   2 +-
 net/ipv4/inet_timewait_sock.c                      |   3 +-
 net/ipv4/ipmr.c                                    |   2 +-
 net/ipv6/ip6mr.c                                   |   2 +-
 net/mac80211/mesh_pathtbl.c                        |   2 +-
 net/netfilter/ipset/ip_set_list_set.c              |   2 +-
 net/netfilter/ipvs/ip_vs_lblc.c                    |   2 +-
 net/netfilter/ipvs/ip_vs_lblcr.c                   |   2 +-
 net/netfilter/xt_LED.c                             |   2 +-
 net/rxrpc/conn_object.c                            |   2 +-
 net/sched/cls_flow.c                               |   2 +-
 net/sunrpc/svc.c                                   |   2 +-
 net/sunrpc/xprt.c                                  |   2 +-
 net/tipc/discover.c                                |   2 +-
 net/tipc/monitor.c                                 |   2 +-
 sound/i2c/other/ak4117.c                           |   2 +-
 sound/synth/emux/emux.c                            |   2 +-
 100 files changed, 310 insertions(+), 175 deletions(-)

[RFC][PATCH v3 19/33] timers: net: Use timer_shutdown_sync() before freeing timer

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

Before a timer is freed, timer_shutdown_sync() must be called.

And if synchronization is already done, then at least timer_shutdown()
needs to be called.

Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home/

Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Mirko Lindner <mlindner@marvell.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Menglong Dong <imagedong@tencent.com>
Cc: linux-usb@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: bridge@lists.linux-foundation.org
Cc: netfilter-devel@vger.kernel.org
Cc: coreteam@netfilter.org
Cc: lvs-devel@vger.kernel.org
Cc: linux-afs@lists.infradead.org
Cc: linux-nfs@vger.kernel.org
Cc: tipc-discussion@lists.sourceforge.net
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c      | 6 +++---
 drivers/net/ethernet/marvell/sky2.c              | 2 +-
 drivers/net/ethernet/sun/sunvnet.c               | 2 +-
 drivers/net/usb/sierra_net.c                     | 2 +-
 drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c | 2 +-
 drivers/net/wireless/intersil/hostap/hostap_ap.c | 2 +-
 drivers/net/wireless/marvell/mwifiex/main.c      | 2 +-
 drivers/net/wireless/microchip/wilc1000/hif.c    | 8 ++++----
 net/802/garp.c                                   | 2 +-
 net/802/mrp.c                                    | 2 +-
 net/bridge/br_multicast.c                        | 6 +++---
 net/bridge/br_multicast_eht.c                    | 4 ++--
 net/core/gen_estimator.c                         | 2 +-
 net/core/neighbour.c                             | 2 ++
 net/ipv4/inet_connection_sock.c                  | 2 +-
 net/ipv4/inet_timewait_sock.c                    | 3 ++-
 net/ipv4/ipmr.c                                  | 2 +-
 net/ipv6/ip6mr.c                                 | 2 +-
 net/mac80211/mesh_pathtbl.c                      | 2 +-
 net/netfilter/ipset/ip_set_list_set.c            | 2 +-
 net/netfilter/ipvs/ip_vs_lblc.c                  | 2 +-
 net/netfilter/ipvs/ip_vs_lblcr.c                 | 2 +-
 net/netfilter/xt_LED.c                           | 2 +-
 net/rxrpc/conn_object.c                          | 2 +-
 net/sched/cls_flow.c                             | 2 +-
 net/sunrpc/svc.c                                 | 2 +-
 net/sunrpc/xprt.c                                | 2 +-
 net/tipc/discover.c                              | 2 +-
 net/tipc/monitor.c                               | 2 +-
 29 files changed, 39 insertions(+), 36 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index b5dcd15ced36..54d5eed32743 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -15530,7 +15530,7 @@ static int i40e_init_recovery_mode(struct i40e_pf *pf, struct i40e_hw *hw)
 
 err_switch_setup:
 	i40e_reset_interrupt_capability(pf);
-	del_timer_sync(&pf->service_timer);
+	timer_shutdown_sync(&pf->service_timer);
 	i40e_shutdown_adminq(hw);
 	iounmap(hw->hw_addr);
 	pci_disable_pcie_error_reporting(pf->pdev);
@@ -16149,7 +16149,7 @@ static int i40e_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	kfree(pf->vsi);
 err_switch_setup:
 	i40e_reset_interrupt_capability(pf);
-	del_timer_sync(&pf->service_timer);
+	timer_shutdown_sync(&pf->service_timer);
 err_mac_addr:
 err_configure_lan_hmc:
 	(void)i40e_shutdown_lan_hmc(hw);
@@ -16211,7 +16211,7 @@ static void i40e_remove(struct pci_dev *pdev)
 	set_bit(__I40E_SUSPENDED, pf->state);
 	set_bit(__I40E_DOWN, pf->state);
 	if (pf->service_timer.function)
-		del_timer_sync(&pf->service_timer);
+		timer_shutdown_sync(&pf->service_timer);
 	if (pf->service_task.func)
 		cancel_work_sync(&pf->service_task);
 
diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c
index ab33ba1c3023..dc571e076180 100644
--- a/drivers/net/ethernet/marvell/sky2.c
+++ b/drivers/net/ethernet/marvell/sky2.c
@@ -5013,7 +5013,7 @@ static void sky2_remove(struct pci_dev *pdev)
 	if (!hw)
 		return;
 
-	del_timer_sync(&hw->watchdog_timer);
+	timer_shutdown_sync(&hw->watchdog_timer);
 	cancel_work_sync(&hw->restart_work);
 
 	for (i = hw->ports-1; i >= 0; --i)
diff --git a/drivers/net/ethernet/sun/sunvnet.c b/drivers/net/ethernet/sun/sunvnet.c
index acda6cbd0238..fe86fbd58586 100644
--- a/drivers/net/ethernet/sun/sunvnet.c
+++ b/drivers/net/ethernet/sun/sunvnet.c
@@ -524,7 +524,7 @@ static void vnet_port_remove(struct vio_dev *vdev)
 		hlist_del_rcu(&port->hash);
 
 		synchronize_rcu();
-		del_timer_sync(&port->clean_timer);
+		timer_shutdown_sync(&port->clean_timer);
 		sunvnet_port_rm_txq_common(port);
 		netif_napi_del(&port->napi);
 		sunvnet_port_free_tx_bufs_common(port);
diff --git a/drivers/net/usb/sierra_net.c b/drivers/net/usb/sierra_net.c
index b3ae949e6f1c..673d3aa83792 100644
--- a/drivers/net/usb/sierra_net.c
+++ b/drivers/net/usb/sierra_net.c
@@ -759,7 +759,7 @@ static void sierra_net_unbind(struct usbnet *dev, struct usb_interface *intf)
 	dev_dbg(&dev->udev->dev, "%s", __func__);
 
 	/* kill the timer and work */
-	del_timer_sync(&priv->sync_timer);
+	timer_shutdown_sync(&priv->sync_timer);
 	cancel_work_sync(&priv->sierra_net_kevent);
 
 	/* tell modem we are going away */
diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
index 3237d4b528b5..119d83acafd1 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
@@ -371,7 +371,7 @@ void iwl_dbg_tlv_del_timers(struct iwl_trans *trans)
 	struct iwl_dbg_tlv_timer_node *node, *tmp;
 
 	list_for_each_entry_safe(node, tmp, timer_list, list) {
-		del_timer_sync(&node->timer);
+		timer_shutdown_sync(&node->timer);
 		list_del(&node->list);
 		kfree(node);
 	}
diff --git a/drivers/net/wireless/intersil/hostap/hostap_ap.c b/drivers/net/wireless/intersil/hostap/hostap_ap.c
index 462ccc7d7d1a..9b546a71e7a2 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_ap.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_ap.c
@@ -135,7 +135,7 @@ static void ap_free_sta(struct ap_data *ap, struct sta_info *sta)
 
 	if (!sta->ap)
 		kfree(sta->u.sta.challenge);
-	del_timer_sync(&sta->timer);
+	timer_shutdown_sync(&sta->timer);
 #endif /* PRISM2_NO_KERNEL_IEEE80211_MGMT */
 
 	kfree(sta);
diff --git a/drivers/net/wireless/marvell/mwifiex/main.c b/drivers/net/wireless/marvell/mwifiex/main.c
index da2e6557e684..ea22a08e6c08 100644
--- a/drivers/net/wireless/marvell/mwifiex/main.c
+++ b/drivers/net/wireless/marvell/mwifiex/main.c
@@ -123,7 +123,7 @@ static int mwifiex_unregister(struct mwifiex_adapter *adapter)
 	if (adapter->if_ops.cleanup_if)
 		adapter->if_ops.cleanup_if(adapter);
 
-	del_timer_sync(&adapter->cmd_timer);
+	timer_shutdown_sync(&adapter->cmd_timer);
 
 	/* Free private structures */
 	for (i = 0; i < adapter->priv_num; i++) {
diff --git a/drivers/net/wireless/microchip/wilc1000/hif.c b/drivers/net/wireless/microchip/wilc1000/hif.c
index eb1d1ba3a443..b76b5ce95961 100644
--- a/drivers/net/wireless/microchip/wilc1000/hif.c
+++ b/drivers/net/wireless/microchip/wilc1000/hif.c
@@ -1520,10 +1520,10 @@ int wilc_deinit(struct wilc_vif *vif)
 
 	mutex_lock(&vif->wilc->deinit_lock);
 
-	del_timer_sync(&hif_drv->scan_timer);
-	del_timer_sync(&hif_drv->connect_timer);
-	del_timer_sync(&vif->periodic_rssi);
-	del_timer_sync(&hif_drv->remain_on_ch_timer);
+	timer_shutdown_sync(&hif_drv->scan_timer);
+	timer_shutdown_sync(&hif_drv->connect_timer);
+	timer_shutdown_sync(&vif->periodic_rssi);
+	timer_shutdown_sync(&hif_drv->remain_on_ch_timer);
 
 	if (hif_drv->usr_scan_req.scan_result) {
 		hif_drv->usr_scan_req.scan_result(SCAN_EVENT_ABORTED, NULL,
diff --git a/net/802/garp.c b/net/802/garp.c
index fc9eb02a912f..87b2ddfe86ac 100644
--- a/net/802/garp.c
+++ b/net/802/garp.c
@@ -618,7 +618,7 @@ void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl
 
 	/* Delete timer and generate a final TRANSMIT_PDU event to flush out
 	 * all pending messages before the applicant is gone. */
-	del_timer_sync(&app->join_timer);
+	timer_shutdown_sync(&app->join_timer);
 
 	spin_lock_bh(&app->lock);
 	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
diff --git a/net/802/mrp.c b/net/802/mrp.c
index 155f74d8b14f..a744a28477dd 100644
--- a/net/802/mrp.c
+++ b/net/802/mrp.c
@@ -904,7 +904,7 @@ void mrp_uninit_applicant(struct net_device *dev, struct mrp_application *appl)
 	 * all pending messages before the applicant is gone.
 	 */
 	del_timer_sync(&app->join_timer);
-	del_timer_sync(&app->periodic_timer);
+	timer_shutdown_sync(&app->periodic_timer);
 
 	spin_lock_bh(&app->lock);
 	mrp_mad_event(app, MRP_EVENT_TX);
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index db4f2641d1cd..16d2a7064e44 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -605,7 +605,7 @@ static void br_multicast_destroy_mdb_entry(struct net_bridge_mcast_gc *gc)
 	WARN_ON(!hlist_unhashed(&mp->mdb_node));
 	WARN_ON(mp->ports);
 
-	del_timer_sync(&mp->timer);
+	timer_shutdown_sync(&mp->timer);
 	kfree_rcu(mp, rcu);
 }
 
@@ -646,7 +646,7 @@ static void br_multicast_destroy_group_src(struct net_bridge_mcast_gc *gc)
 	src = container_of(gc, struct net_bridge_group_src, mcast_gc);
 	WARN_ON(!hlist_unhashed(&src->node));
 
-	del_timer_sync(&src->timer);
+	timer_shutdown_sync(&src->timer);
 	kfree_rcu(src, rcu);
 }
 
@@ -671,7 +671,7 @@ static void br_multicast_destroy_port_group(struct net_bridge_mcast_gc *gc)
 	WARN_ON(!hlist_empty(&pg->src_list));
 
 	del_timer_sync(&pg->rexmit_timer);
-	del_timer_sync(&pg->timer);
+	timer_shutdown_sync(&pg->timer);
 	kfree_rcu(pg, rcu);
 }
 
diff --git a/net/bridge/br_multicast_eht.c b/net/bridge/br_multicast_eht.c
index f91c071d1608..c126aa4e7551 100644
--- a/net/bridge/br_multicast_eht.c
+++ b/net/bridge/br_multicast_eht.c
@@ -142,7 +142,7 @@ static void br_multicast_destroy_eht_set_entry(struct net_bridge_mcast_gc *gc)
 	set_h = container_of(gc, struct net_bridge_group_eht_set_entry, mcast_gc);
 	WARN_ON(!RB_EMPTY_NODE(&set_h->rb_node));
 
-	del_timer_sync(&set_h->timer);
+	timer_shutdown_sync(&set_h->timer);
 	kfree(set_h);
 }
 
@@ -154,7 +154,7 @@ static void br_multicast_destroy_eht_set(struct net_bridge_mcast_gc *gc)
 	WARN_ON(!RB_EMPTY_NODE(&eht_set->rb_node));
 	WARN_ON(!RB_EMPTY_ROOT(&eht_set->entry_tree));
 
-	del_timer_sync(&eht_set->timer);
+	timer_shutdown_sync(&eht_set->timer);
 	kfree(eht_set);
 }
 
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 4fcbdd71c59f..fae9c4694186 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -208,7 +208,7 @@ void gen_kill_estimator(struct net_rate_estimator __rcu **rate_est)
 
 	est = xchg((__force struct net_rate_estimator **)rate_est, NULL);
 	if (est) {
-		del_timer_sync(&est->timer);
+		timer_shutdown_sync(&est->timer);
 		kfree_rcu(est, rcu);
 	}
 }
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 3c4786b99907..68edfd46781c 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -895,6 +895,8 @@ void neigh_destroy(struct neighbour *neigh)
 	if (neigh_del_timer(neigh))
 		pr_warn("Impossible event\n");
 
+	timer_shutdown(&neigh->timer);
+
 	write_lock_bh(&neigh->lock);
 	__skb_queue_purge(&neigh->arp_queue);
 	write_unlock_bh(&neigh->lock);
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 4e84ed21d16f..5e70228c5ae9 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -917,7 +917,7 @@ static bool reqsk_queue_unlink(struct request_sock *req)
 		found = __sk_nulls_del_node_init_rcu(sk);
 		spin_unlock(lock);
 	}
-	if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer))
+	if (timer_pending(&req->rsk_timer) && timer_shutdown_sync(&req->rsk_timer))
 		reqsk_put(req);
 	return found;
 }
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 66fc940f9521..8a70bb726bcb 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -66,6 +66,7 @@ static void inet_twsk_kill(struct inet_timewait_sock *tw)
 void inet_twsk_free(struct inet_timewait_sock *tw)
 {
 	struct module *owner = tw->tw_prot->owner;
+	timer_shutdown(&tw->tw_timer);
 	twsk_destructor((struct sock *)tw);
 #ifdef SOCK_REFCNT_DEBUG
 	pr_debug("%s timewait_sock %p released\n", tw->tw_prot->name, tw);
@@ -208,7 +209,7 @@ EXPORT_SYMBOL_GPL(inet_twsk_alloc);
  */
 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw)
 {
-	if (del_timer_sync(&tw->tw_timer))
+	if (timer_shutdown_sync(&tw->tw_timer))
 		inet_twsk_kill(tw);
 	inet_twsk_put(tw);
 }
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index e04544ac4b45..dbaf4c33b155 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -412,7 +412,7 @@ static struct mr_table *ipmr_new_table(struct net *net, u32 id)
 
 static void ipmr_free_table(struct mr_table *mrt)
 {
-	del_timer_sync(&mrt->ipmr_expire_timer);
+	timer_shutdown_sync(&mrt->ipmr_expire_timer);
 	mroute_clean_tables(mrt, MRT_FLUSH_VIFS | MRT_FLUSH_VIFS_STATIC |
 				 MRT_FLUSH_MFC | MRT_FLUSH_MFC_STATIC);
 	rhltable_destroy(&mrt->mfc_hash);
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index facdc78a43e5..474b862039e0 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -392,7 +392,7 @@ static struct mr_table *ip6mr_new_table(struct net *net, u32 id)
 
 static void ip6mr_free_table(struct mr_table *mrt)
 {
-	del_timer_sync(&mrt->ipmr_expire_timer);
+	timer_shutdown_sync(&mrt->ipmr_expire_timer);
 	mroute_clean_tables(mrt, MRT6_FLUSH_MIFS | MRT6_FLUSH_MIFS_STATIC |
 				 MRT6_FLUSH_MFC | MRT6_FLUSH_MFC_STATIC);
 	rhltable_destroy(&mrt->mfc_hash);
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index acc1c299f1ae..ec72756075f5 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -512,7 +512,7 @@ static void mesh_path_free_rcu(struct mesh_table *tbl,
 	mpath->flags |= MESH_PATH_RESOLVING | MESH_PATH_DELETED;
 	mesh_gate_del(tbl, mpath);
 	spin_unlock_bh(&mpath->state_lock);
-	del_timer_sync(&mpath->timer);
+	timer_shutdown_sync(&mpath->timer);
 	atomic_dec(&sdata->u.mesh.mpaths);
 	atomic_dec(&tbl->entries);
 	mesh_path_flush_pending(mpath);
diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
index 5a67f7966574..e162636525cf 100644
--- a/net/netfilter/ipset/ip_set_list_set.c
+++ b/net/netfilter/ipset/ip_set_list_set.c
@@ -427,7 +427,7 @@ list_set_destroy(struct ip_set *set)
 	struct set_elem *e, *n;
 
 	if (SET_WITH_TIMEOUT(set))
-		del_timer_sync(&map->gc);
+		timer_shutdown_sync(&map->gc);
 
 	list_for_each_entry_safe(e, n, &map->members, list) {
 		list_del(&e->list);
diff --git a/net/netfilter/ipvs/ip_vs_lblc.c b/net/netfilter/ipvs/ip_vs_lblc.c
index 7ac7473e3804..1b87214d385e 100644
--- a/net/netfilter/ipvs/ip_vs_lblc.c
+++ b/net/netfilter/ipvs/ip_vs_lblc.c
@@ -384,7 +384,7 @@ static void ip_vs_lblc_done_svc(struct ip_vs_service *svc)
 	struct ip_vs_lblc_table *tbl = svc->sched_data;
 
 	/* remove periodic timer */
-	del_timer_sync(&tbl->periodic_timer);
+	timer_shutdown_sync(&tbl->periodic_timer);
 
 	/* got to clean up table entries here */
 	ip_vs_lblc_flush(svc);
diff --git a/net/netfilter/ipvs/ip_vs_lblcr.c b/net/netfilter/ipvs/ip_vs_lblcr.c
index 77c323c36a88..ad8f5fea6d3a 100644
--- a/net/netfilter/ipvs/ip_vs_lblcr.c
+++ b/net/netfilter/ipvs/ip_vs_lblcr.c
@@ -547,7 +547,7 @@ static void ip_vs_lblcr_done_svc(struct ip_vs_service *svc)
 	struct ip_vs_lblcr_table *tbl = svc->sched_data;
 
 	/* remove periodic timer */
-	del_timer_sync(&tbl->periodic_timer);
+	timer_shutdown_sync(&tbl->periodic_timer);
 
 	/* got to clean up table entries here */
 	ip_vs_lblcr_flush(svc);
diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c
index 0371c387b0d1..66b0f941d8fb 100644
--- a/net/netfilter/xt_LED.c
+++ b/net/netfilter/xt_LED.c
@@ -166,7 +166,7 @@ static void led_tg_destroy(const struct xt_tgdtor_param *par)
 
 	list_del(&ledinternal->list);
 
-	del_timer_sync(&ledinternal->timer);
+	timer_shutdown_sync(&ledinternal->timer);
 
 	led_trigger_unregister(&ledinternal->netfilter_led_trigger);
 
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 22089e37e97f..307d6d480e78 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -358,7 +358,7 @@ static void rxrpc_destroy_connection(struct rcu_head *rcu)
 
 	_net("DESTROY CONN %d", conn->debug_id);
 
-	del_timer_sync(&conn->timer);
+	timer_shutdown_sync(&conn->timer);
 	rxrpc_purge_queue(&conn->rx_queue);
 
 	conn->security->clear(conn);
diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index 014cd3de7b5d..cd90a3083b9f 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -367,7 +367,7 @@ static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
 
 static void __flow_destroy_filter(struct flow_filter *f)
 {
-	del_timer_sync(&f->perturb_timer);
+	timer_shutdown_sync(&f->perturb_timer);
 	tcf_exts_destroy(&f->exts);
 	tcf_em_tree_destroy(&f->ematches);
 	tcf_exts_put_net(&f->exts);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 149171774bc6..42663e240ec5 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -567,7 +567,7 @@ svc_destroy(struct kref *ref)
 	struct svc_serv *serv = container_of(ref, struct svc_serv, sv_refcnt);
 
 	dprintk("svc: svc_destroy(%s)\n", serv->sv_program->pg_name);
-	del_timer_sync(&serv->sv_temptimer);
+	timer_shutdown_sync(&serv->sv_temptimer);
 
 	/*
 	 * The last user is gone and thus all sockets have to be destroyed to
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index ab453ede54f0..311718ce26d0 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -2118,7 +2118,7 @@ static void xprt_destroy(struct rpc_xprt *xprt)
 	 * can only run *before* del_time_sync(), never after.
 	 */
 	spin_lock(&xprt->transport_lock);
-	del_timer_sync(&xprt->timer);
+	timer_shutdown_sync(&xprt->timer);
 	spin_unlock(&xprt->transport_lock);
 
 	/*
diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index e8630707901e..d9efbee90fb4 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -385,7 +385,7 @@ int tipc_disc_create(struct net *net, struct tipc_bearer *b,
  */
 void tipc_disc_delete(struct tipc_discoverer *d)
 {
-	del_timer_sync(&d->timer);
+	timer_shutdown_sync(&d->timer);
 	kfree_skb(d->skb);
 	kfree(d);
 }
diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
index 9618e4429f0f..77a3d016cade 100644
--- a/net/tipc/monitor.c
+++ b/net/tipc/monitor.c
@@ -700,7 +700,7 @@ void tipc_mon_delete(struct net *net, int bearer_id)
 	}
 	mon->self = NULL;
 	write_unlock_bh(&mon->lock);
-	del_timer_sync(&mon->timer);
+	timer_shutdown_sync(&mon->timer);
 	kfree(self->domain);
 	kfree(self);
 	kfree(mon);
-- 
2.35.1

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Linus Torvalds]

On Thu, Nov 3, 2022 at 10:48 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Ideally, I would have the first patch go into this rc cycle, which is mostly
> non functional as it will allow the other patches to come in via the respective
> subsystems in the next merge window.

Ack.

I also wonder if we could do the completely trivially correct
conversions immediately.

I'm talking about the scripted ones where it's currently a
"del_timer_sync()", and the very next action is freeing whatever data
structure the timer is in (possibly with something like free_irq() in
between - my point is that there's an unconditional free that is very
clear and unambiguous), so that there is absolutely no question about
whether they should use "timer_shutdown_sync()" or not.

IOW, things like patches 03, 17 and 31, and at least parts others in
this series.

This series clearly has several much more complex cases that need
actual real code review, and I think it would help to have the
completely unambiguous cases out of the way, just to get rid of noise.

So I'd take that first patch, and a scripted set of "this cannot
change any semantics" patches early.

                Linus

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Guenter Roeck]

On Fri, Nov 04, 2022 at 01:40:53AM -0400, Steven Rostedt wrote:
> 
> Back in April, I posted an RFC patch set to help mitigate a common issue
> where a timer gets armed just before it is freed, and when the timer
> goes off, it crashes in the timer code without any evidence of who the
> culprit was. I got side tracked and never finished up on that patch set.
> Since this type of crash is still our #1 crash we are seeing in the field,
> it has become a priority again to finish it.
> 
> This is v3 of that patch set. Thomas Gleixner posted an untested version
> that makes timer->function NULL as the flag that it is shutdown. I took that
> code, tested it (fixed it up), added more comments, and changed the
> name to timer_shutdown_sync(). I also converted it to use WARN_ON_ONCE()
> instead of just WARN_ON() as Linus asked for.
> 

Unfortunately the renaming caused some symbol conflicts.

Global definition: timer_shutdown

  File             Line
0 time.c            93 static inline void timer_shutdown(struct clock_event_device *evt)
1 arm_arch_timer.c 690 static __always_inline int timer_shutdown(const int access,
2 timer-fttmr010.c 105 int (*timer_shutdown)(struct clock_event_device *evt);
3 timer-sp804.c    158 static inline void timer_shutdown(struct clock_event_device *evt)
4 timer.h          239 static inline int timer_shutdown(struct timer_list *timer)

Guenter

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Steven Rostedt]

On Fri, 4 Nov 2022 12:22:32 -0700
Guenter Roeck <linux@roeck-us.net> wrote:

> Unfortunately the renaming caused some symbol conflicts.
> 
> Global definition: timer_shutdown
> 
>   File             Line
> 0 time.c            93 static inline void timer_shutdown(struct clock_event_device *evt)
> 1 arm_arch_timer.c 690 static __always_inline int timer_shutdown(const int access,
> 2 timer-fttmr010.c 105 int (*timer_shutdown)(struct clock_event_device *evt);
> 3 timer-sp804.c    158 static inline void timer_shutdown(struct clock_event_device *evt)
> 4 timer.h          239 static inline int timer_shutdown(struct timer_list *timer)

$ git grep '\btimer_shutdown'
arch/arm/mach-spear/time.c:static inline void timer_shutdown(struct clock_event_device *evt)
arch/arm/mach-spear/time.c:     timer_shutdown(evt);
arch/arm/mach-spear/time.c:     timer_shutdown(evt);
arch/arm/mach-spear/time.c:     timer_shutdown(evt);
drivers/clocksource/arm_arch_timer.c:static __always_inline int timer_shutdown(const int access,
drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
drivers/clocksource/timer-fttmr010.c:   int (*timer_shutdown)(struct clock_event_device *evt);
drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = ast2600_timer_shutdown;
drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = fttmr010_timer_shutdown;
drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.set_state_shutdown = fttmr010->timer_shutdown;
drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.tick_resume = fttmr010->timer_shutdown;
drivers/clocksource/timer-sp804.c:static inline void timer_shutdown(struct clock_event_device *evt)
drivers/clocksource/timer-sp804.c:      timer_shutdown(evt);
drivers/clocksource/timer-sp804.c:      timer_shutdown(evt);

Honestly, I think these need to be renamed, as "timer_shutdown()"
should be specific to the timer code, and not individual timers.

I'll start making a patch set that starts by renaming these timers,
then adds the timer_shutdown() API, and finished with the trivial
updates, and that will be a real "PATCH" (non RFC).

Linus, should I also add any patches that has already been acked by the
respective maintainer?

-- Steve

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Linus Torvalds]

On Fri, Nov 4, 2022 at 12:42 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Linus, should I also add any patches that has already been acked by the
> respective maintainer?

No, I'd prefer to keep only the ones that are 100% unambiguously not
changing any semantics.

              Linus

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Steven Rostedt]

On Fri, 4 Nov 2022 15:42:09 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> $ git grep '\btimer_shutdown'
> arch/arm/mach-spear/time.c:static inline void timer_shutdown(struct clock_event_device *evt)
> arch/arm/mach-spear/time.c:     timer_shutdown(evt);
> arch/arm/mach-spear/time.c:     timer_shutdown(evt);
> arch/arm/mach-spear/time.c:     timer_shutdown(evt);
> drivers/clocksource/arm_arch_timer.c:static __always_inline int timer_shutdown(const int access,
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
> drivers/clocksource/timer-fttmr010.c:   int (*timer_shutdown)(struct clock_event_device *evt);



> drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = ast2600_timer_shutdown;
> drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = fttmr010_timer_shutdown;
> drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.set_state_shutdown = fttmr010->timer_shutdown;
> drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.tick_resume = fttmr010->timer_shutdown;

I won't touch structure fields though.

-- Steve


> drivers/clocksource/timer-sp804.c:static inline void timer_shutdown(struct clock_event_device *evt)
> drivers/clocksource/timer-sp804.c:      timer_shutdown(evt);
> drivers/clocksource/timer-sp804.c:      timer_shutdown(evt);

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Guenter Roeck]

On Fri, Nov 04, 2022 at 03:42:09PM -0400, Steven Rostedt wrote:
> On Fri, 4 Nov 2022 12:22:32 -0700
> Guenter Roeck <linux@roeck-us.net> wrote:
> 
> > Unfortunately the renaming caused some symbol conflicts.
> > 
> > Global definition: timer_shutdown
> > 
> >   File             Line
> > 0 time.c            93 static inline void timer_shutdown(struct clock_event_device *evt)
> > 1 arm_arch_timer.c 690 static __always_inline int timer_shutdown(const int access,
> > 2 timer-fttmr010.c 105 int (*timer_shutdown)(struct clock_event_device *evt);
> > 3 timer-sp804.c    158 static inline void timer_shutdown(struct clock_event_device *evt)
> > 4 timer.h          239 static inline int timer_shutdown(struct timer_list *timer)
> 
> $ git grep '\btimer_shutdown'
> arch/arm/mach-spear/time.c:static inline void timer_shutdown(struct clock_event_device *evt)
> arch/arm/mach-spear/time.c:     timer_shutdown(evt);
> arch/arm/mach-spear/time.c:     timer_shutdown(evt);
> arch/arm/mach-spear/time.c:     timer_shutdown(evt);
> drivers/clocksource/arm_arch_timer.c:static __always_inline int timer_shutdown(const int access,
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
> drivers/clocksource/arm_arch_timer.c:   return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
> drivers/clocksource/timer-fttmr010.c:   int (*timer_shutdown)(struct clock_event_device *evt);
> drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = ast2600_timer_shutdown;
> drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = fttmr010_timer_shutdown;
> drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.set_state_shutdown = fttmr010->timer_shutdown;
> drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.tick_resume = fttmr010->timer_shutdown;
> drivers/clocksource/timer-sp804.c:static inline void timer_shutdown(struct clock_event_device *evt)
> drivers/clocksource/timer-sp804.c:      timer_shutdown(evt);
> drivers/clocksource/timer-sp804.c:      timer_shutdown(evt);
> 
> Honestly, I think these need to be renamed, as "timer_shutdown()"
> should be specific to the timer code, and not individual timers.

Yes, that is what I did locally. I am repeating my test now with that
change made.

Guenter

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Guenter Roeck]

On Fri, Nov 04, 2022 at 04:38:34PM -0400, Steven Rostedt wrote:
> On Fri, 4 Nov 2022 15:42:09 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
[ ... ]
> 
> > drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> > drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> > drivers/clocksource/timer-fttmr010.c:   fttmr010->timer_shutdown(evt);
> > drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = ast2600_timer_shutdown;
> > drivers/clocksource/timer-fttmr010.c:           fttmr010->timer_shutdown = fttmr010_timer_shutdown;
> > drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.set_state_shutdown = fttmr010->timer_shutdown;
> > drivers/clocksource/timer-fttmr010.c:   fttmr010->clkevt.tick_resume = fttmr010->timer_shutdown;
> 
> I won't touch structure fields though.
> 

Agreed, same here.

Guenter

Re: [RFC][PATCH v3 00/33] timers: Use timer_shutdown*() before freeing timers

[Guenter Roeck]

On Fri, Nov 04, 2022 at 01:40:53AM -0400, Steven Rostedt wrote:
> 
> Back in April, I posted an RFC patch set to help mitigate a common issue
> where a timer gets armed just before it is freed, and when the timer
> goes off, it crashes in the timer code without any evidence of who the
> culprit was. I got side tracked and never finished up on that patch set.
> Since this type of crash is still our #1 crash we are seeing in the field,
> it has become a priority again to finish it.
> 

After applying the patches attached below, everything compiles for me,
and there are no crashes. There are still various warnings, most in
networking. I know I need to apply some patch(es) to fix the networking
warnings, but I didn't entirely understand what exactly to apply, so
I didn't try.

Complete logs are at https://kerneltests.org/builders, on the bottom half
of the page (qemu tests, in the 'testing' column).

Guenter

---
Warnings:

ODEBUG: free active (active state 0) object type: timer_list hint: tcp_write_timer+0x0/0x1d0
	from tcp_close -> __sk_destruct -> tcp_write_timer

ODEBUG: free active (active state 0) object type: timer_list hint: tcp_keepalive_timer+0x0/0x4c0
	from tcp_close -> __sk_destruct -> tcp_keepalive_timer -> __del_timer_sync

ODEBUG: free active (active state 0) object type: timer_list hint: blk_rq_timed_out_timer+0x0/0x40
	blk_free_queue_rcu -> blk_free_queue_rcu -> blk_rq_timed_out_timer

---
Changes applied on top of patch set to fix build errors:

diff --git a/arch/arm/mach-spear/time.c b/arch/arm/mach-spear/time.c
index e979e2197f8e..5371c824786d 100644
--- a/arch/arm/mach-spear/time.c
+++ b/arch/arm/mach-spear/time.c
@@ -90,7 +90,7 @@ static void __init spear_clocksource_init(void)
 		200, 16, clocksource_mmio_readw_up);
 }
 
-static inline void timer_shutdown(struct clock_event_device *evt)
+static inline void spear_timer_shutdown(struct clock_event_device *evt)
 {
 	u16 val = readw(gpt_base + CR(CLKEVT));
 
@@ -101,7 +101,7 @@ static inline void timer_shutdown(struct clock_event_device *evt)
 
 static int spear_shutdown(struct clock_event_device *evt)
 {
-	timer_shutdown(evt);
+	spear_timer_shutdown(evt);
 
 	return 0;
 }
@@ -111,7 +111,7 @@ static int spear_set_oneshot(struct clock_event_device *evt)
 	u16 val;
 
 	/* stop the timer */
-	timer_shutdown(evt);
+	spear_timer_shutdown(evt);
 
 	val = readw(gpt_base + CR(CLKEVT));
 	val |= CTRL_ONE_SHOT;
@@ -126,7 +126,7 @@ static int spear_set_periodic(struct clock_event_device *evt)
 	u16 val;
 
 	/* stop the timer */
-	timer_shutdown(evt);
+	spear_timer_shutdown(evt);
 
 	period = clk_get_rate(gpt_clk) / HZ;
 	period >>= CTRL_PRESCALER16;
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index a7ff77550e17..9c3420a0d19d 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -687,8 +687,8 @@ static irqreturn_t arch_timer_handler_virt_mem(int irq, void *dev_id)
 	return timer_handler(ARCH_TIMER_MEM_VIRT_ACCESS, evt);
 }
 
-static __always_inline int timer_shutdown(const int access,
-					  struct clock_event_device *clk)
+static __always_inline int arch_timer_shutdown(const int access,
+					       struct clock_event_device *clk)
 {
 	unsigned long ctrl;
 
@@ -701,22 +701,22 @@ static __always_inline int timer_shutdown(const int access,
 
 static int arch_timer_shutdown_virt(struct clock_event_device *clk)
 {
-	return timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
+	return arch_timer_shutdown(ARCH_TIMER_VIRT_ACCESS, clk);
 }
 
 static int arch_timer_shutdown_phys(struct clock_event_device *clk)
 {
-	return timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
+	return arch_timer_shutdown(ARCH_TIMER_PHYS_ACCESS, clk);
 }
 
 static int arch_timer_shutdown_virt_mem(struct clock_event_device *clk)
 {
-	return timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
+	return arch_timer_shutdown(ARCH_TIMER_MEM_VIRT_ACCESS, clk);
 }
 
 static int arch_timer_shutdown_phys_mem(struct clock_event_device *clk)
 {
-	return timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
+	return arch_timer_shutdown(ARCH_TIMER_MEM_PHYS_ACCESS, clk);
 }
 
 static __always_inline void set_next_event(const int access, unsigned long evt,
diff --git a/drivers/clocksource/timer-sp804.c b/drivers/clocksource/timer-sp804.c
index e6a87f4af2b5..a3c38e1343f0 100644
--- a/drivers/clocksource/timer-sp804.c
+++ b/drivers/clocksource/timer-sp804.c
@@ -155,14 +155,14 @@ static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static inline void timer_shutdown(struct clock_event_device *evt)
+static inline void sp804_timer_shutdown(struct clock_event_device *evt)
 {
 	writel(0, common_clkevt->ctrl);
 }
 
 static int sp804_shutdown(struct clock_event_device *evt)
 {
-	timer_shutdown(evt);
+	sp804_timer_shutdown(evt);
 	return 0;
 }
 
@@ -171,7 +171,7 @@ static int sp804_set_periodic(struct clock_event_device *evt)
 	unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE |
 			     TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
 
-	timer_shutdown(evt);
+	sp804_timer_shutdown(evt);
 	writel(common_clkevt->reload, common_clkevt->load);
 	writel(ctrl, common_clkevt->ctrl);
 	return 0;