tmakin/tegra-linux-noble
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

workqueue: Add rcu lock check at the end of work item execution

Browse Source 
BugLink: https://bugs.launchpad.net/bugs/2106770

[ Upstream commit 1a65a6d17cbc58e1aeffb2be962acce49efbef9c ]

Currently the workqueue just checks the atomic and locking states after work
execution ends. However, sometimes, a work item may not unlock rcu after
acquiring rcu_read_lock(). And as a result, it would cause rcu stall, but
the rcu stall warning can not dump the work func, because the work has
finished.

In order to quickly discover those works that do not call rcu_read_unlock()
after rcu_read_lock(), add the rcu lock check.

Use rcu_preempt_depth() to check the work's rcu status. Normally, this value
is 0. If this value is bigger than 0, it means the work are still holding
rcu lock. If so, print err info and the work func.

tj: Reworded the description for clarity. Minor formatting tweak.

Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Stable-dep-of: de35994ecd2d ("workqueue: Do not warn when cancelling WQ_MEM_RECLAIM work from !WQ_MEM_RECLAIM worker")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Mehmet Basaran <mehmet.basaran@canonical.com>
This commit is contained in:
Xuewen Yan
2024-01-10 11:27:24 +08:00
committed by Mehmet Basaran
parent 4cabec444b
commit 3b1618d24e
1 changed files with 5 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/workqueue.c
+5 -4
View File
@@ -2648,11 +2648,12 @@ __acquires(&pool->lock)
lock_map_release(&lockdep_map);
lock_map_release(&pwq->wq->lockdep_map);
if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
if (unlikely(in_atomic() || lockdep_depth(current) > 0 ||
rcu_preempt_depth() > 0)) {
pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d/%d\n"
" last function: %ps\n",
current->comm, preempt_count(), task_pid_nr(current),
worker->current_func);
current->comm, preempt_count(), rcu_preempt_depth(),
task_pid_nr(current), worker->current_func);
debug_show_held_locks(current);
dump_stack();
}