diff options
| author | Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr> | 2023-08-26 16:51:03 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2023-08-29 09:52:16 -1000 |
| commit | fe48ba7daefe75bbbefa2426deddc05f2d530d2d (patch) | |
| tree | d8d2580b8adcaaf36987c62f214477def09fef0b /kernel/workqueue.c | |
| parent | b6a46f7263bd8ba0e545d79bd034c412f32b5875 (diff) | |
workqueue: fix data race with the pwq->stats[] increment
KCSAN has discovered a data race in kernel/workqueue.c:2598:
[ 1863.554079] ==================================================================
[ 1863.554118] BUG: KCSAN: data-race in process_one_work / process_one_work
[ 1863.554142] write to 0xffff963d99d79998 of 8 bytes by task 5394 on cpu 27:
[ 1863.554154] process_one_work (kernel/workqueue.c:2598)
[ 1863.554166] worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2752)
[ 1863.554177] kthread (kernel/kthread.c:389)
[ 1863.554186] ret_from_fork (arch/x86/kernel/process.c:145)
[ 1863.554197] ret_from_fork_asm (arch/x86/entry/entry_64.S:312)
[ 1863.554213] read to 0xffff963d99d79998 of 8 bytes by task 5450 on cpu 12:
[ 1863.554224] process_one_work (kernel/workqueue.c:2598)
[ 1863.554235] worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2752)
[ 1863.554247] kthread (kernel/kthread.c:389)
[ 1863.554255] ret_from_fork (arch/x86/kernel/process.c:145)
[ 1863.554266] ret_from_fork_asm (arch/x86/entry/entry_64.S:312)
[ 1863.554280] value changed: 0x0000000000001766 -> 0x000000000000176a
[ 1863.554295] Reported by Kernel Concurrency Sanitizer on:
[ 1863.554303] CPU: 12 PID: 5450 Comm: kworker/u64:1 Tainted: G L 6.5.0-rc6+ #44
[ 1863.554314] Hardware name: ASRock X670E PG Lightning/X670E PG Lightning, BIOS 1.21 04/26/2023
[ 1863.554322] Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]
[ 1863.554941] ==================================================================
lockdep_invariant_state(true);
→ pwq->stats[PWQ_STAT_STARTED]++;
trace_workqueue_execute_start(work);
worker->current_func(work);
Moving pwq->stats[PWQ_STAT_STARTED]++; before the line
raw_spin_unlock_irq(&pool->lock);
resolves the data race without performance penalty.
KCSAN detected at least one additional data race:
[ 157.834751] ==================================================================
[ 157.834770] BUG: KCSAN: data-race in process_one_work / process_one_work
[ 157.834793] write to 0xffff9934453f77a0 of 8 bytes by task 468 on cpu 29:
[ 157.834804] process_one_work (/home/marvin/linux/kernel/linux_torvalds/kernel/workqueue.c:2606)
[ 157.834815] worker_thread (/home/marvin/linux/kernel/linux_torvalds/./include/linux/list.h:292 /home/marvin/linux/kernel/linux_torvalds/kernel/workqueue.c:2752)
[ 157.834826] kthread (/home/marvin/linux/kernel/linux_torvalds/kernel/kthread.c:389)
[ 157.834834] ret_from_fork (/home/marvin/linux/kernel/linux_torvalds/arch/x86/kernel/process.c:145)
[ 157.834845] ret_from_fork_asm (/home/marvin/linux/kernel/linux_torvalds/arch/x86/entry/entry_64.S:312)
[ 157.834859] read to 0xffff9934453f77a0 of 8 bytes by task 214 on cpu 7:
[ 157.834868] process_one_work (/home/marvin/linux/kernel/linux_torvalds/kernel/workqueue.c:2606)
[ 157.834879] worker_thread (/home/marvin/linux/kernel/linux_torvalds/./include/linux/list.h:292 /home/marvin/linux/kernel/linux_torvalds/kernel/workqueue.c:2752)
[ 157.834890] kthread (/home/marvin/linux/kernel/linux_torvalds/kernel/kthread.c:389)
[ 157.834897] ret_from_fork (/home/marvin/linux/kernel/linux_torvalds/arch/x86/kernel/process.c:145)
[ 157.834907] ret_from_fork_asm (/home/marvin/linux/kernel/linux_torvalds/arch/x86/entry/entry_64.S:312)
[ 157.834920] value changed: 0x000000000000052a -> 0x0000000000000532
[ 157.834933] Reported by Kernel Concurrency Sanitizer on:
[ 157.834941] CPU: 7 PID: 214 Comm: kworker/u64:2 Tainted: G L 6.5.0-rc7-kcsan-00169-g81eaf55a60fc #4
[ 157.834951] Hardware name: ASRock X670E PG Lightning/X670E PG Lightning, BIOS 1.21 04/26/2023
[ 157.834958] Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]
[ 157.835567] ==================================================================
in code:
trace_workqueue_execute_end(work, worker->current_func);
→ pwq->stats[PWQ_STAT_COMPLETED]++;
lock_map_release(&lockdep_map);
lock_map_release(&pwq->wq->lockdep_map);
which needs to be resolved separately.
Fixes: 725e8ec59c56c ("workqueue: Add pwq->stats[] and a monitoring script")
Cc: Tejun Heo <tj@kernel.org>
Suggested-by: Lai Jiangshan <jiangshanlai@gmail.com>
Link: https://lore.kernel.org/lkml/20230818194448.29672-1-mirsad.todorovac@alu.unizg.hr/
Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@alu.unizg.hr>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index d4364d3d8aaa..c85825e17df8 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2599,6 +2599,7 @@ __acquires(&pool->lock) */ set_work_pool_and_clear_pending(work, pool->id); + pwq->stats[PWQ_STAT_STARTED]++; raw_spin_unlock_irq(&pool->lock); lock_map_acquire(&pwq->wq->lockdep_map); @@ -2625,7 +2626,6 @@ __acquires(&pool->lock) * workqueues), so hiding them isn't a problem. */ lockdep_invariant_state(true); - pwq->stats[PWQ_STAT_STARTED]++; trace_workqueue_execute_start(work); worker->current_func(work); /* |