Re: [PATCH v4 1/4] mm: Don't skip swap entry even if zap_details specified

[Andrew Morton]

On Wed, 16 Feb 2022 17:48:07 +0800 Peter Xu <peterx@xxxxxxxxxx> wrote:

> The "details" pointer shouldn't be the token to decide whether we should skip
> swap entries.  For example, when the user specified details->zap_mapping==NULL,
> it means the user wants to zap all the pages (including COWed pages), then we
> need to look into swap entries because there can be private COWed pages that
> was swapped out.

I assume "user" here means "caller".

> Skipping some swap entries when details is non-NULL may lead to wrongly leaving
> some of the swap entries while we should have zapped them.
> 
> A reproducer of the problem:
> 
> ...
>
> The issue seems to exist starting from the initial commit of git.

I'll add cc:stable to this one, thanks.