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From: SeongJae Park <sj@kernel.org>
To: Junxi Qian <qjx1298677004@gmail.com>
Cc: SeongJae Park <sj@kernel.org>,
	akpm@linux-foundation.org,
	damon@lists.linux.dev,
	linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH] mm/damon/sysfs-schemes: fix use-after-free on memcg_path and goal path
Date: Tue, 21 Apr 2026 16:47:30 -0700
Message-ID: <20260421234730.2917-1-sj@kernel.org>
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On Tue, 21 Apr 2026 15:06:32 +0800 Junxi Qian <qjx1298677004@gmail.com> 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

[...]