Re: [PATCH] mm/damon/core: fix potential memory leak by cleaning ops_filter in damon_destroy_scheme

[Enze Li <lienze@kylinos.cn>]

Hi SJ,

On Tue, Oct 14 2025 at 11:25:38 AM -0700, SeongJae Park wrote:

> On Tue, 14 Oct 2025 16:42:25 +0800 Enze Li <lienze@kylinos.cn> wrote:
>
>> Currently, damon_destroy_scheme() only cleans up the filter list but
>> leaves ops_filter untouched, which could lead to memory leaks when
>> a scheme is destroyed.
>> 
>> This patch ensures both filter and ops_filter are properly freed in
>> damon_destroy_scheme(), preventing potential memory leaks.
>
> Thank you for fixing this!
>
> FYI the leak is not only potential but can easily be reproduced using the ops
> damos filters.  For example, I was able to reproduce it using DAMON user-space
> tool (damo), like below.
>
>     $ sudo ./damo start
>     $ sudo ./damo report access --snapshot_damos_filter allow anon
>
> After the above steps I confirmed it leaks the memory using kmemleak.

Thank you for the review.

Considering that similar memory leak issues might occur elsewhere in the
future, should we consider exploring the introduction of Rust for
certain modules as a proactive measure?

My search through the mailing list archives didn't reveal similar
discussions, though I might have missed them.  Would you be open to
sharing your insights on this matter?

Best Regards,
Enze

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