[PATCH 6.8 070/172] pds_core: Fix pdsc_check_pci_health function to use work thread

Greg Kroah-Hartman
2024-04-15T14:26:55Z

From: Brett Creeley <brett.creeley@amd.com>

[ Upstream commit 81665adf25d28a00a986533f1d3a5df76b79cad9 ]

When the driver notices fw_status == 0xff it tries to perform a PCI
reset on itself via pci_reset_function() in the context of the driver's
health thread. However, pdsc_reset_prepare calls
pdsc_stop_health_thread(), which attempts to stop/flush the health
thread. This results in a deadlock because the stop/flush will never
complete since the driver called pci_reset_function() from the health
thread context. Fix by changing the pdsc_check_pci_health_function()
to queue a newly introduced pdsc_pci_reset_thread() on the pdsc's
work queue.

Unloading the driver in the fw_down/dead state uncovered another issue,
which can be seen in the following trace:

WARNING: CPU: 51 PID: 6914 at kernel/workqueue.c:1450 __queue_work+0x358/0x440
[...]
RIP: 0010:__queue_work+0x358/0x440
[...]
Call Trace:
<TASK>
? __warn+0x85/0x140
? __queue_work+0x358/0x440
? report_bug+0xfc/0x1e0
? handle_bug+0x3f/0x70
? exc_invalid_op+0x17/0x70
? asm_exc_invalid_op+0x1a/0x20
? __queue_work+0x358/0x440
queue_work_on+0x28/0x30
pdsc_devcmd_locked+0x96/0xe0 [pds_core]
pdsc_devcmd_reset+0x71/0xb0 [pds_core]
pdsc_teardown+0x51/0xe0 [pds_core]
pdsc_remove+0x106/0x200 [pds_core]
pci_device_remove+0x37/0xc0
device_release_driver_internal+0xae/0x140
driver_detach+0x48/0x90
bus_remove_driver+0x6d/0xf0
pci_unregister_driver+0x2e/0xa0
pdsc_cleanup_module+0x10/0x780 [pds_core]
__x64_sys_delete_module+0x142/0x2b0
? syscall_trace_enter.isra.18+0x126/0x1a0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7fbd9d03a14b
[...]

Fix this by preventing the devcmd reset if the FW is not running.

Fixes: d9407ff11809 ("pds_core: Prevent health thread from running during reset/remove")
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/amd/pds_core/core.c | 13 ++++++++++++-
drivers/net/ethernet/amd/pds_core/core.h | 2 ++
drivers/net/ethernet/amd/pds_core/dev.c | 3 +++
drivers/net/ethernet/amd/pds_core/main.c | 1 +
4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/amd/pds_core/core.c b/drivers/net/ethernet/amd/pds_core/core.c
index 0d148795a8d09..dd4f0965bbe64 100644
--- a/drivers/net/ethernet/amd/pds_core/core.c
+++ b/drivers/net/ethernet/amd/pds_core/core.c
@@ -595,6 +595,16 @@ void pdsc_fw_up(struct pdsc *pdsc)
pdsc_teardown(pdsc, PDSC_TEARDOWN_RECOVERY);
}

+void pdsc_pci_reset_thread(struct work_struct *work)
+{
+ struct pdsc *pdsc = container_of(work, struct pdsc, pci_reset_work);
+ struct pci_dev *pdev = pdsc->pdev;
+
+ pci_dev_get(pdev);
+ pci_reset_function(pdev);
+ pci_dev_put(pdev);
+}
+
static void pdsc_check_pci_health(struct pdsc *pdsc)
{
u8 fw_status;
@@ -609,7 +619,8 @@ static void pdsc_check_pci_health(struct pdsc *pdsc)
if (fw_status != PDS_RC_BAD_PCI)
return;

- pci_reset_function(pdsc->pdev);
+ /* prevent deadlock between pdsc_reset_prepare and pdsc_health_thread */
+ queue_work(pdsc->wq, &pdsc->pci_reset_work);
}

void pdsc_health_thread(struct work_struct *work)
diff --git a/drivers/net/ethernet/amd/pds_core/core.h b/drivers/net/ethernet/amd/pds_core/core.h
index f410f7d132056..401ff56eba0dc 100644
--- a/drivers/net/ethernet/amd/pds_core/core.h
+++ b/drivers/net/ethernet/amd/pds_core/core.h
@@ -197,6 +197,7 @@ struct pdsc {
struct pdsc_qcq notifyqcq;
u64 last_eid;
struct pdsc_viftype *viftype_status;
+ struct work_struct pci_reset_work;
};

/** enum pds_core_dbell_bits - bitwise composition of dbell values.
@@ -312,5 +313,6 @@ int pdsc_firmware_update(struct pdsc *pdsc, const struct firmware *fw,

void pdsc_fw_down(struct pdsc *pdsc);
void pdsc_fw_up(struct pdsc *pdsc);
+void pdsc_pci_reset_thread(struct work_struct *work);

#endif /* _PDSC_H_ */
diff --git a/drivers/net/ethernet/amd/pds_core/dev.c b/drivers/net/ethernet/amd/pds_core/dev.c
index e65a1632df505..bfb79c5aac391 100644
--- a/drivers/net/ethernet/amd/pds_core/dev.c
+++ b/drivers/net/ethernet/amd/pds_core/dev.c
@@ -229,6 +229,9 @@ int pdsc_devcmd_reset(struct pdsc *pdsc)
.reset.opcode = PDS_CORE_CMD_RESET,
};

+ if (!pdsc_is_fw_running(pdsc))
+ return 0;
+
return pdsc_devcmd(pdsc, &cmd, &comp, pdsc->devcmd_timeout);
}

diff --git a/drivers/net/ethernet/amd/pds_core/main.c b/drivers/net/ethernet/amd/pds_core/main.c
index 345b16127fe8b..a375d612d2875 100644
--- a/drivers/net/ethernet/amd/pds_core/main.c
+++ b/drivers/net/ethernet/amd/pds_core/main.c
@@ -238,6 +238,7 @@ static int pdsc_init_pf(struct pdsc *pdsc)
snprintf(wq_name, sizeof(wq_name), "%s.%d", PDS_CORE_DRV_NAME, pdsc->uid);
pdsc->wq = create_singlethread_workqueue(wq_name);
INIT_WORK(&pdsc->health_work, pdsc_health_thread);
+ INIT_WORK(&pdsc->pci_reset_work, pdsc_pci_reset_thread);
timer_setup(&pdsc->wdtimer, pdsc_wdtimer_cb, 0);
pdsc->wdtimer_period = PDSC_WATCHDOG_SECS * HZ;

--
2.43.0