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=1793831477; b=RziOZwhrYtDMhAu+7UBswxju0KBlt6Q8GpQEUv9khj3UVTIl+W7ZzNA2oK5Ll+gIkerx +PpBGarCwnsO9FLiu5NQUAU04f4MXELvFT87ee9NQ7/UtaTzQ0CEKuTltYJ5mgU8gj9Ab tuqAnS8k1XKQswGc2o42f6hp0ah9MBUw19IXja2sa3lb8dB+sTcKUfo2uGu9whW/x0+tp 78r2aJqMshg0ZR9WeV7CIelUj5ZWMhVT0JIKIzEashlm6/g/6Ubro1TucaSUqT64uXJzF SumOzvSt3kFbwlP72RQI30AlNSaURVhORhcpk8uMLs7ZJ0I1BdIJzCkVBgAAgypNJ+A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831477; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=EFYWagbdaJ/Dg4ucioCkGic+H7BL5U0AKytV9tydK/k=; b=iJTTyW1Lsrp4aqtnzwaHkIeCN4Ij5ryoMgLGcP0FCvDOv37jhP+OLDx11i6+82BLNPBM Vc/QNfcre6N+ZRaHC2GTfhbJjko303DeiIbT0iSJx/vdBYAPBQ26DEfIFd6CNFJekH3gE oVHYiRiuZptlUWj22eYnCnQa36ZRJYNvUwVgkglQnQV9UdbLjyXYLcgd3CkZZ55Xl+VHG l3V3pgwaYpY9tYBF093ntNPYtuuovcYajxtbfeCZCMHNzSVGY8juDLPFq7c452rL73jFn 9Qoshv+2CtQmF6uzr07iR2T+srbxd8JZSl0eK1a4KPQ0rlCiyIekK2PIfUHFW6fC7ZA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=JWaGbq5G; 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 5E75C606AC2A; Wed, 4 Nov 2026 22:31:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=JWaGbq5G Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC0EF1F000C1; Wed, 4 Nov 2026 22:31:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831477; bh=EFYWagbdaJ/Dg4ucioCkGic+H7BL5U0AKytV9tydK/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JWaGbq5G3LLKZVmQ/G7YiJlUXUGQSFcbjUYyJd9jDXksf3pLWJ4HUg+IFAbAZaKNx CVxMRc/lF+hZY28BdWoDBZHZhvqnjlSrilrCyGkbbIo4q/sQ9txXtrJAJ7jga+0UlR iCF3T7d6TOd6PqIT8WbObljounIvwnQAyZtxCcrs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andrzej Hajda , Fan Wu , Marek Szyprowski , Nicolas Dufresne , Hans Verkuil Subject: [PATCH 6.18 0728/1005] media: s5p-mfc: use timer_shutdown_sync() for the self-rearming watchdog Date: Wed, 4 Nov 2026 16:07:41 -0500 Message-ID: <20261104211103.891532101@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Fan Wu commit 63069b5917cba2e15b1a78b3f4ff99e45102c56f upstream. 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 Signed-off-by: Greg Kroah-Hartman --- drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c +++ b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c @@ -1474,8 +1474,8 @@ static void s5p_mfc_remove(struct platfo } mutex_unlock(&dev->mfc_mutex); - timer_delete_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);