Re: [PATCH] mm/damon/sysfs-schemes: fix use-after-free on memcg_path and goal path

[junxi qian]

Hi SJ,

Thank you for the suggestion and for offering to help.

It would be great if you could finish the remaining work. Please feel
free to add my Co-developed-by: and Signed-off-by: tags.

Thanks,
Junxi

On Wed, Apr 22, 2026 at 7:47 AM SeongJae Park <sj@xxxxxxxxxx> wrote:
>
> On Tue, 21 Apr 2026 15:06:32 +0800 Junxi Qian <qjx1298677004@xxxxxxxxx> wrote:
>
> > Hi SJ,
> >
> > Thanks for the suggestion.
> >
> > I checked the show/store race further and was able to reproduce the
> > memcg_path_show() side issue on a KASAN kernel.
>
> Thank you for sharing this, Jinxi!
>
> [...]
> > I will spend some time thinking about how to fix this properly.
> >
> > If someone more familiar with this code would like to work on the fix
> > directly, that would be greatly appreciated, as I am not very familiar
> > with this part of the code yet.
>
> I think you could protect the memcg_path and path load/store() parts with the
> damon_sysfs_lock, but using mutex_trylock() instead of mutex_lock(), as I
> suggested.  If you prefer me to finish the remaining work, please feel free to
> let me know.  If that's the case, I will work on the fix while adding
> Co-developed-by: and Signed-off-by: tags of you on the fix, if you don't mind.
>
>
> Thanks,
> SJ
>
> [...]