Date:   Mon, 27 Dec 2021 13:35:40 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     SeongJae Park <sj@kernel.org>
Cc:     stable@vger.kernel.org, akpm@linux-foundation.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] mm/damon/dbgfs: protect targets destructions with
 kdamond_lock
Message-ID: <YcmzHCJYiYIMcyTH@kroah.com>
References: <20211226102632.836-1-sj@kernel.org>
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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@kernel.org
> Reported-by: Sangwoo Bae <sangwoob@amazon.com>
> Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
> Signed-off-by: SeongJae Park <sj@kernel.org>
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> ---
> 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