From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793836293; b=eKI1DknuxpUkNz0NT9OQtJRH0r/dmWnoU51JiRdZXiMKs7JHgaFkT836NXXZ6YjlA2v9 WH39yB4iJ4T6ukljzoHwKQ7YfxoI4LY+0LflO4k2dyJ2A2jgRv8pdJBCsY+SWTclkURI9 xl3dil5UQ7B5xqjHRRm/oPLFSs6tPY8Pey4UcrwyLd13gLZxnglCOqdznhValIh0aDmDw +kmN/K9YSPNdzzCnQ8UNqb8x7X/idVYr5nm+19MonTg56WOOJNb8KVHb5p5RtCUs8aLMt GAMfFSWLrCLo3m5Q0SK9m1BkxynOlHfNKnZs3r9KDYPIFn9tava9nMuFF13wG4T7dgg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793836293; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=Sfry1kHkGoI00sEuShgmwRE319huUyE47/fhH9PZ1BI=; b=r2ZJrDlxHQUoUOIF3E6iJzyq0rj1kk2WWGkFm9UQV7CKyMMjxX1Gp6JfKQIdFU3VSZmT no7NNs2e6hzhNpk1W6CPrflrIO1jZN5PbkdhJVZIUOtVqpCpa1CB0rGVrQA5SyfaortyO Ljnmz1XZCwhGwp4Q3RKzl+f3xkA8v7YqTitJxJk6D6U4SR4QS7aj/01r5yX7iMfaJf11Q CKy8cgWcLfG7IcRUprxzFX/Yo8RbEjuWe3/L/2RYvD2FvxC7giKyqyxwhmKqzphJtRN9z QTgMnsXiG+ljjwnTFDzDt44Zg5Ui0DgpwekB84nCEqIOZyvgz0m1H6bDnYYEVhcvmnw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=i4mTzMnt; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1F4D606A31B for ; Wed, 4 Nov 2026 23:51:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=i4mTzMnt Received: by smtp.kernel.org (Postfix) with ESMTPSA id B92D81F000C1; Wed, 4 Nov 2026 23:51:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793836292; bh=Sfry1kHkGoI00sEuShgmwRE319huUyE47/fhH9PZ1BI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=i4mTzMntw4qHEogkpu7JKztYTZUhg6YgDJdMYL6xgiFs4uZ+iIKAHH9ZPYzP4bTpj gBWDypyvIWV0mLBteFLD3wAHC3PR15uV8X4BGaOUZY4oBNNHPjnRJ9Fmhehnn5RTBx 0J9ZOuGnC96LE7iUb6miFe+YlY7sa+jwi2F+n3wEoOnh38Ww7gSC3zZNn+vjfl3+7T 3dfmH3AkoiJYpHhR1Mew6I4W/uIiXOhcXys2cu44GvisFnsC/NUd8qwk//Y0RzimZT DdSj5k3npJbbxf6kutXnWewIYQZm0NeTJxUqa3QgzwO0pLUWre2Jm1gT95CgkzrtMx VLcjkSEMR53gQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Fan Wu , Andrzej Hajda , Marek Szyprowski , Nicolas Dufresne , Hans Verkuil , Sasha Levin Subject: [PATCH 6.6.y] media: s5p-mfc: use timer_shutdown_sync() for the self-rearming watchdog Date: Wed, 4 Nov 2026 18:51:30 -0500 Message-ID: <20261104235107.950691-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110426-scrutiny-value-3242@gregkh> References: <2026110426-scrutiny-value-3242@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Fan Wu [ Upstream commit 63069b5917cba2e15b1a78b3f4ff99e45102c56f ] The MFC watchdog timer (s5p_mfc_watchdog) is self-rearming: every callback re-arms itself with add_timer() and, on a timeout, schedules watchdog_work. s5p_mfc_remove() tears this down with timer_delete_sync() followed by flush_work(). timer_delete_sync() dequeues the timer and waits for a callback that is already running, but it does not prevent a subsequent re-arm. Because the watchdog callback re-arms via add_timer(), this is the wrong shutdown primitive: once the wait returns nothing guarantees a just-queued re-arm will not fire later, dereferencing dev (clock on/off, deinit_hw, load_firmware, init_hw) after video_unregister_device(), DMA teardown and s5p_mfc_final_pm() have run, a potential use-after-free. Use timer_shutdown_sync(), which puts the timer into a shutdown state so that any add_timer()/mod_timer() from the callback becomes a no-op and no later firing is possible. Switch flush_work() to cancel_work_sync() so any watchdog_work that was already queued before the timer was stopped is cancelled rather than allowed to run to completion against the torn-down device. This issue was found by an in-house static analysis tool. No runtime reproducer is available. Fixes: af9357467810 ("[media] MFC: Add MFC 5.1 V4L2 driver") Cc: stable@vger.kernel.org Cc: Andrzej Hajda Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu Reviewed-by: Marek Szyprowski Signed-off-by: Nicolas Dufresne Signed-off-by: Hans Verkuil [ sashal: adjusted context for del_timer_sync() instead of timer_delete_sync() ] Signed-off-by: Sasha Levin --- drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c index e30e54935d79a..1386208b092f5 100644 --- a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c +++ b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c @@ -1454,8 +1454,8 @@ static void s5p_mfc_remove(struct platform_device *pdev) } mutex_unlock(&dev->mfc_mutex); - del_timer_sync(&dev->watchdog_timer); - flush_work(&dev->watchdog_work); + timer_shutdown_sync(&dev->watchdog_timer); + cancel_work_sync(&dev->watchdog_work); video_unregister_device(dev->vfd_enc); video_unregister_device(dev->vfd_dec); -- 2.53.0