Re: [PATCH] mm/damon/dbgfs: protect targets destructions with kdamond_lock

[Greg KH]

On Sun, Dec 26, 2021 at 10:26:32AM +0000, SeongJae Park wrote:
> commit 34796417964b8d0aef45a99cf6c2d20cebe33733 upstream.
> 
> DAMON debugfs interface iterates current monitoring targets in
> 'dbgfs_target_ids_read()' while holding the corresponding
> 'kdamond_lock'.  However, it also destructs the monitoring targets in
> 'dbgfs_before_terminate()' without holding the lock.  This can result in
> a use_after_free bug.  This commit avoids the race by protecting the
> destruction with the corresponding 'kdamond_lock'.
> 
> Link: https://lkml.kernel.org/r/20211221094447.2241-1-sj@xxxxxxxxxx
> Reported-by: Sangwoo Bae <sangwoob@xxxxxxxxxx>
> Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
> Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.15.x
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> ---
> This is a backport of a DAMON fix that merged in the mainline, for
> v5.15.x stable series.

Now queued up, thanks.

greg k-h