From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2949378F26 for ; Fri, 3 Oct 2025 19:32:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759519952; cv=none; b=F99lyLbq1jnWHKnNcbrHZm4RxPB5V+62wdlbP+KMowEmH5VmE2BnR5WN3v1Bt990oM7aBlDeTD2s8tlAYLZraEySm1+33wYB3IgkP6fK6jidoxHeNxIGpEemH5OlGP3yYDQniudk0Y8hT8DFd8WJVW+W3nX/4F1sdITPjiH7E4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759519952; c=relaxed/simple; bh=hF51D3+mOVx4or+38FUJ8pzrNs5XeCs3vLi1r7zW64w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iIp2W4vxbJ07Fq+95xp+ESUAKyTZsLcgEvo0zfzh7LdZQxfQZiyhtqcZ9KYtpKqixMuabv6EGas9mK2VxHzRkrq+hV8CaPusjb5ksSRlLoSvv6yTXw2iR5zzOlpYIRp0GuFW7gQ79uBFtf3sLxT3kkIROH8wbBJnCzpA8hLdZbA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Nw62yZbV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Nw62yZbV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 316B5C4CEF9; Fri, 3 Oct 2025 19:32:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759519951; bh=hF51D3+mOVx4or+38FUJ8pzrNs5XeCs3vLi1r7zW64w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Nw62yZbVisUePBWNMvXxP6yaDtZGa6Y31wIxqPpDA6+WgSr1O1XAK2jgU7AaNegiy JZ4q7gCZ14v1/OSDD7Bmvs8sjhiLKYMKv8RbXcCeGpujstuybuogaSROTxrhcf4AGW dTqIhmOTEhlrAMTdu1F1xbBWuMU3EWUUBBkZbS01pmLJcSjyC/nclPCVBUUMX5+jzo PApPul+IxzzdqS9PF4RSEemDkBjDJt+qPKZeui6Wc1vs8DwqTUb+SiUBmlpJiDX6vL mbdXsyuk9oCLv3/8c4PC7VKHAVZBrX7vZ6U2c8NYGY4rY7GtMM8MvG7lkDNz9CeCpw PVD7PGKwCQtRQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Duoming Zhou , Hans Verkuil , Sasha Levin Subject: [PATCH 6.6.y 2/2] media: tuner: xc5000: Fix use-after-free in xc5000_release Date: Fri, 3 Oct 2025 15:32:28 -0400 Message-ID: <20251003193228.3339889-2-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251003193228.3339889-1-sashal@kernel.org> References: <2025100338-ambulance-swaddling-4b2b@gregkh> <20251003193228.3339889-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Duoming Zhou [ Upstream commit 40b7a19f321e65789612ebaca966472055dab48c ] The original code uses cancel_delayed_work() in xc5000_release(), which does not guarantee that the delayed work item timer_sleep has fully completed if it was already running. This leads to use-after-free scenarios where xc5000_release() may free the xc5000_priv while timer_sleep is still active and attempts to dereference the xc5000_priv. A typical race condition is illustrated below: CPU 0 (release thread) | CPU 1 (delayed work callback) xc5000_release() | xc5000_do_timer_sleep() cancel_delayed_work() | hybrid_tuner_release_state(priv) | kfree(priv) | | priv = container_of() // UAF Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure that the timer_sleep is properly canceled before the xc5000_priv memory is deallocated. A deadlock concern was considered: xc5000_release() is called in a process context and is not holding any locks that the timer_sleep work item might also need. Therefore, the use of the _sync() variant is safe here. This bug was initially identified through static analysis. Fixes: f7a27ff1fb77 ("[media] xc5000: delay tuner sleep to 5 seconds") Cc: stable@vger.kernel.org Signed-off-by: Duoming Zhou Signed-off-by: Hans Verkuil [hverkuil: fix typo in Subject: tunner -> tuner] Signed-off-by: Sasha Levin --- drivers/media/tuners/xc5000.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/tuners/xc5000.c b/drivers/media/tuners/xc5000.c index 30aa4ee958bde..ec9a3cd4784e1 100644 --- a/drivers/media/tuners/xc5000.c +++ b/drivers/media/tuners/xc5000.c @@ -1304,7 +1304,7 @@ static void xc5000_release(struct dvb_frontend *fe) mutex_lock(&xc5000_list_mutex); if (priv) { - cancel_delayed_work(&priv->timer_sleep); + cancel_delayed_work_sync(&priv->timer_sleep); hybrid_tuner_release_state(priv); } -- 2.51.0