2020-08-25 02:00:07

by Walter Wu

Subject: [PATCH v3 2/6] workqueue: kasan: record workqueue stack

Records the last two enqueuing work call stacks in order to print them
in KASAN report. It is useful for programmers to solve use-after-free
or double-free memory workqueue issue.

For workqueue it has turned out to be useful to record the enqueuing
work call stacks. Because user can see KASAN report to determine
whether it is root cause. They don't need to enable debugobjects,
but they have a chance to find out the root cause.

Signed-off-by: Walter Wu <[email protected]>
Suggested-by: Marco Elver <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Lai Jiangshan <[email protected]>
---

v2:
- Thanks for Marco suggestion.
- Remove unnecessary code
- reuse kasan_record_aux_stack() and aux_stack
to record timer and workqueue stack

---

kernel/workqueue.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c41c3c17b86a..5fea7dc9180f 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1324,6 +1324,9 @@ static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
{
struct worker_pool *pool = pwq->pool;

+ /* record the work call stack in order to print it in KASAN reports */
+ kasan_record_aux_stack(work);
+
/* we own @work, set data and link */
set_work_pwq(work, pwq, extra_flags);
list_add_tail(&work->entry, head);
--
2.18.0

2020-09-02 14:55:49

by Tejun Heo

Subject: Re: [PATCH v3 2/6] workqueue: kasan: record workqueue stack

On Tue, Aug 25, 2020 at 09:58:33AM +0800, Walter Wu wrote:
> Records the last two enqueuing work call stacks in order to print them
> in KASAN report. It is useful for programmers to solve use-after-free
> or double-free memory workqueue issue.
>
> For workqueue it has turned out to be useful to record the enqueuing
> work call stacks. Because user can see KASAN report to determine
> whether it is root cause. They don't need to enable debugobjects,
> but they have a chance to find out the root cause.
>
> Signed-off-by: Walter Wu <[email protected]>
> Suggested-by: Marco Elver <[email protected]>
> Cc: Andrey Ryabinin <[email protected]>
> Cc: Dmitry Vyukov <[email protected]>
> Cc: Alexander Potapenko <[email protected]>
> Cc: Tejun Heo <[email protected]>
> Cc: Lai Jiangshan <[email protected]>

Acked-by: Tejun Heo <[email protected]>

Thanks.

--
tejun