Re: [PATCH] mm/kmemleak: Prevent soft lockup in kmemleak_scan()'s object iteration loops

From: Waiman Long
Date: Thu Oct 20 2022 - 21:22:27 EST



On 10/20/22 20:58, Andrew Morton wrote:
On Thu, 20 Oct 2022 13:56:19 -0400 Waiman Long <longman@xxxxxxxxxx> wrote:

Commit 6edda04ccc7c ("mm/kmemleak: prevent soft lockup in first object
iteration loop of kmemleak_scan()") adds cond_resched() in the first
object iteration loop of kmemleak_scan(). However, it turns that the
2nd objection iteration loop can still cause soft lockup to happen in
some cases. So add a cond_resched() call in the 2nd and 3rd loops as
well to prevent that and for completeness.

Seems reasonable, although not an object of beauty.

We didn't include a Fixes: or cc:stable in 6edda04ccc7c, even though it
addresses softlockups. I think I'll add a cc:stable to this, with a
Fixes:6edda04ccc7c. So any kenrel which included 6edda04ccc7c will
hopefully add this as well.

That sounds good to me. I consider commit 6edda04ccc7c incomplete and this patch complete it. Technically it can be considered a fix.

Thanks,
Longman