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=1794061867; b=VXMr0S+ef/Ql+zAH3npfa2twyF5PlfPt8cBCoQyEN0as8BNg326pyxuo2mOAqh6mP3KA Ex3HuhVlwlRbNW0tEb0J9d/K2Nj2oiyZB7YLty8+GLumuvYe6uJ6npCr1+oaAh/Y5b/gT d1wdi2GRD8KgcM353MMzfBfJccR8UKor+6OaPqOIc3ykpcEqJ+thimpTIuXvT9YQnoozr hiFXma5gCxEQV3YxSXERKwYwyBKdPwTWIEGmSUxsbA1kQE7vCQUw7x6QAk/FLipZ1fbCP uyl3FlRlrtTFGF0m+PSYdbRIOItrK8l8UsqVC/XyYDbz41f4Y+XQyfi1g8ifhAsZ9Dg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061867; 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=lN4S0OPjgmJ8BqdkP/0SISCP8nNyHDTWMn2P0ztt0a8=; b=lM3fndKC9EZ3gP4sDKRceliuFjeEH4AsR9Owop87B0pgTzoLyKPaCOWAQ7gL7gvQFbAY KGz5+Jdx1lL9kV1HssVR8zRziozEkT0/xYETM1Ywv/WC5+mt0uBXzvt5XVd9cZtJ5Onrf iOJ/B7feqC8PFxzqe4UYRAymlWW9m8k8a26RcViR1zJ7bcodxA9ByNcjvUKlEdkdsouTE ubWm+8RvOHbi0nofottB1W230uCUWQkWNj+0WFFygn4xakwNOdhKCvXpxnPXguAW8Pv4J 8cT3m3sBlKPEPG4ZhcdtgS5OC54nQOIVvBs7zceWJ//eGtrKdTKAkozEGvMoTxQYVdg== 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=kjFosJRZ; 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 E5B96606A326; Sat, 7 Nov 2026 14:31:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=kjFosJRZ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 974771F0089F; Sat, 7 Nov 2026 14:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061866; bh=lN4S0OPjgmJ8BqdkP/0SISCP8nNyHDTWMn2P0ztt0a8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kjFosJRZ3lrLo8w7N1MLWW42z7ufNIuVqUEnTWYyvC126o1m3cZ7peKXTC9NGcT7m JSM5Mm4cxcH9MMSSvNGrg0+EeA0ZHsMn6h2SjI8hRommdl0PaOV37kyyWM+kUddoZM MFP9Sqk7RiTGekpb7zlK8Z3NuiQ3MWhx/l1I4Y+E= 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 , Sasha Levin Subject: [PATCH 6.12 0883/1536] media: s5p-mfc: use timer_shutdown_sync() for the self-rearming watchdog Date: Sat, 7 Nov 2026 08:48:19 -0500 Message-ID: <20261107135022.426543026@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ 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: adapted the timer replacement to remove 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 50451984d59f7..eb844ddfd8a2d 100644 --- a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c +++ b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c @@ -1458,8 +1458,8 @@ 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