2020-07-03 06:37:31

by Zhang, Qiang

Subject: [PATCH] kthread: work could not be queued when worker being destroyed

From: Zhang Qiang <[email protected]>

The queuing_blocked func should returns true when the worker
being destroyed.

Signed-off-by: Zhang Qiang <[email protected]>
---
kernel/kthread.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 1166f2043e67..2ca711d0e78a 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -791,7 +791,7 @@ static inline bool queuing_blocked(struct kthread_worker *worker,
{
lockdep_assert_held(&worker->lock);

- return !list_empty(&work->node) || work->canceling;
+ return !list_empty(&work->node) || work->canceling || !worker->task;
}

static void kthread_insert_work_sanity_check(struct kthread_worker *worker,
--
2.24.1

2020-07-03 08:12:11

by Petr Mladek

Subject: Re: [PATCH] kthread: work could not be queued when worker being destroyed

On Thu 2020-07-02 12:49:46, [email protected] wrote:
> From: Zhang Qiang <[email protected]>
>
> The queuing_blocked func should returns true when the worker
> being destroyed.

Queuing work when the worker is not running usually means
a bad design on the API user side. The work is never done
and some job has not finished correctly. We should not go
over it quietly.

> Signed-off-by: Zhang Qiang <[email protected]>
> ---
> kernel/kthread.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/kthread.c b/kernel/kthread.c
> index 1166f2043e67..2ca711d0e78a 100644
> --- a/kernel/kthread.c
> +++ b/kernel/kthread.c
> @@ -791,7 +791,7 @@ static inline bool queuing_blocked(struct kthread_worker *worker,
> {
> lockdep_assert_held(&worker->lock);

A better solution would be:

if (WARN_ON(!worker->task)
return true;


> - return !list_empty(&work->node) || work->canceling;
> + return !list_empty(&work->node) || work->canceling || !worker->task;
> }
>
> static void kthread_insert_work_sanity_check(struct kthread_worker *worker,

Best Regards,
Petr