This is a note to let you know that I've just added the patch titled
net/tg3: resolve deadlock in tg3_reset_task() during EEH
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-tg3-resolve-deadlock-in-tg3_reset_task-during-ee.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 413df5f732aecdd7da275dac8d7bde1fee7b5871
Author: David Christensen <drc@xxxxxxxxxxxxxxxxxx>
Date: Tue Jan 24 13:53:39 2023 -0500
net/tg3: resolve deadlock in tg3_reset_task() during EEH
[ Upstream commit 6c4ca03bd890566d873e3593b32d034bf2f5a087 ]
During EEH error injection testing, a deadlock was encountered in the tg3
driver when tg3_io_error_detected() was attempting to cancel outstanding
reset tasks:
crash> foreach UN bt
...
PID: 159 TASK: c0000000067c6000 CPU: 8 COMMAND: "eehd"
...
#5 [c00000000681f990] __cancel_work_timer at c00000000019fd18
#6 [c00000000681fa30] tg3_io_error_detected at c00800000295f098 [tg3]
#7 [c00000000681faf0] eeh_report_error at c00000000004e25c
...
PID: 290 TASK: c000000036e5f800 CPU: 6 COMMAND: "kworker/6:1"
...
#4 [c00000003721fbc0] rtnl_lock at c000000000c940d8
#5 [c00000003721fbe0] tg3_reset_task at c008000002969358 [tg3]
#6 [c00000003721fc60] process_one_work at c00000000019e5c4
...
PID: 296 TASK: c000000037a65800 CPU: 21 COMMAND: "kworker/21:1"
...
#4 [c000000037247bc0] rtnl_lock at c000000000c940d8
#5 [c000000037247be0] tg3_reset_task at c008000002969358 [tg3]
#6 [c000000037247c60] process_one_work at c00000000019e5c4
...
PID: 655 TASK: c000000036f49000 CPU: 16 COMMAND: "kworker/16:2"
...:1
#4 [c0000000373ebbc0] rtnl_lock at c000000000c940d8
#5 [c0000000373ebbe0] tg3_reset_task at c008000002969358 [tg3]
#6 [c0000000373ebc60] process_one_work at c00000000019e5c4
...
Code inspection shows that both tg3_io_error_detected() and
tg3_reset_task() attempt to acquire the RTNL lock at the beginning of
their code blocks. If tg3_reset_task() should happen to execute between
the times when tg3_io_error_deteced() acquires the RTNL lock and
tg3_reset_task_cancel() is called, a deadlock will occur.
Moving tg3_reset_task_cancel() call earlier within the code block, prior
to acquiring RTNL, prevents this from happening, but also exposes another
deadlock issue where tg3_reset_task() may execute AFTER
tg3_io_error_detected() has executed:
crash> foreach UN bt
PID: 159 TASK: c0000000067d2000 CPU: 9 COMMAND: "eehd"
...
#4 [c000000006867a60] rtnl_lock at c000000000c940d8
#5 [c000000006867a80] tg3_io_slot_reset at c0080000026c2ea8 [tg3]
#6 [c000000006867b00] eeh_report_reset at c00000000004de88
...
PID: 363 TASK: c000000037564000 CPU: 6 COMMAND: "kworker/6:1"
...
#3 [c000000036c1bb70] msleep at c000000000259e6c
#4 [c000000036c1bba0] napi_disable at c000000000c6b848
#5 [c000000036c1bbe0] tg3_reset_task at c0080000026d942c [tg3]
#6 [c000000036c1bc60] process_one_work at c00000000019e5c4
...
This issue can be avoided by aborting tg3_reset_task() if EEH error
recovery is already in progress.
Fixes: db84bf43ef23 ("tg3: tg3_reset_task() needs to use rtnl_lock to synchronize")
Signed-off-by: David Christensen <drc@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Pavan Chebbi <pavan.chebbi@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230124185339.225806-1-drc@xxxxxxxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 3279a6e48f3b..e0eacfc46dd4 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -11158,7 +11158,7 @@ static void tg3_reset_task(struct work_struct *work)
rtnl_lock();
tg3_full_lock(tp, 0);
- if (!netif_running(tp->dev)) {
+ if (tp->pcierr_recovery || !netif_running(tp->dev)) {
tg3_flag_clear(tp, RESET_TASK_PENDING);
tg3_full_unlock(tp);
rtnl_unlock();
@@ -18190,6 +18190,9 @@ static pci_ers_result_t tg3_io_error_detected(struct pci_dev *pdev,
netdev_info(netdev, "PCI I/O error detected\n");
+ /* Want to make sure that the reset task doesn't run */
+ tg3_reset_task_cancel(tp);
+
rtnl_lock();
/* Could be second call or maybe we don't have netdev yet */
@@ -18206,9 +18209,6 @@ static pci_ers_result_t tg3_io_error_detected(struct pci_dev *pdev,
tg3_timer_stop(tp);
- /* Want to make sure that the reset task doesn't run */
- tg3_reset_task_cancel(tp);
-
netif_device_detach(netdev);
/* Clean up software state, even if MMIO is blocked */
