Re: [RFC PATCH v2 2/8] mm/damon/sysfs-schemes: read sysfs_filter->sz_range only once

[sashiko-bot@kernel.org]

> DAMON sysfs interface reads the user-provided size range arguments for
> hugepage_size type DAMOS filter twice.  Once for validation, and once
> again for assignments to the variable that will be passed to the core
> layer.  If the user updates the arguments in parallel, an invalid size
> range could be passed to the core layer.  Avoid it by doing the
> assignments first, and then validating the assigned variables before
> passing those to the core layer.
> 
> User impact of the bug should be trivial.  From the core layer's
> perspective, the invalid size range is not really invalid.  It just
> works as having a weird size range.  No critical issues such as a crash
> or a leak could happen.  And sane users ain't do such parallel arguments
> update anyway.  If they do, such racy behavior is arguably somewhat
> expected and deserved.  That said, there is no reason to keep such
> races.
> 
> Fixes: ea1f204ba29a ("mm/damon/sysfs-schemes: add files for setting damos_filter->sz_range")
> Cc: <stable@vger.kernel.org> # 6.15.x
> Signed-off-by: SJ Park <sj@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260913171706.103052-1-sj@kernel.org?part=2