From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 633CF3DBD51; Wed, 30 Sep 2026 19:19:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795988; cv=none; b=HvIKW923NXhQi82hdpG2GYOzYyRsPeeqJkTw8a5nkjehjPDPAHlu55wEX8MGDTjJUNzTq4ugZ9bm8VrrbdNO788haPoAFKznX4E1Iddu4ASp/nVww0DEj3+J66kIvU5bOHkPX6Ao1K47Yy2/NxHGh+cDLbWy8ttaL1kp0oyYWVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790795988; c=relaxed/simple; bh=zG31NLZ4Wskbybxk7HgI4RuNwO6JeGZimkuHc6icC6M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Lf8y18gwzJeMvjBx0NmGd/JodAxD14QA6jb5ISvl5razCHPNEp8rvjspYduMkLpLabUC2/dwyf08lYSoRhIGoL1hQsBcFcLolQ3srnymhTCy/PbGfV6Qw6hQFh8HPCEcIpDeOSf0xWcju5K2YRZn2VI7T97W0sputQodTC146zs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=X45vX1Y7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="X45vX1Y7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FD321F000FF; Wed, 30 Sep 2026 19:19:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790795987; bh=f4lUhVwKGNfy+aMFsdzk27jlyW6BBT3jdfAgrwDlY2o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=X45vX1Y7nxZtwpxcaWYRqEKqMGicS7zqLDPzbf0gHZDT3NkXcR9JfVSVmxEKZKNk+ qfPa/N2R8cYTTcTd5FtY0IAkGArxgU5LhZ/Lr89Di/85opL94CAeUixthqUODnApe1 KNefN7i6Xk5s8N1iIARCWGYwFReZcrCGaJg0MCTI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , Frank Li , Logan Gunthorpe , Shivank Garg , Vinod Koul , Sasha Levin Subject: [PATCH 6.6 0752/1193] dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() Date: Wed, 30 Sep 2026 17:23:56 +0200 Message-ID: <20260930152450.959325860@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152434.301151190@linuxfoundation.org> References: <20260930152434.301151190@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shivank Garg [ Upstream commit e873c74132f0c5f1452816cd9bb26208f0bba1e1 ] When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/dma/dmaengine.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index daaab1078d050..7d13fc966a80f 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -493,10 +493,13 @@ static int dma_chan_get(struct dma_chan *chan) */ static void dma_chan_put(struct dma_chan *chan) { + struct module *owner; + /* This channel is not in use, bail out */ if (!chan->client_count) return; + owner = dma_chan_to_owner(chan); chan->client_count--; /* This channel is not in use anymore, free it */ @@ -516,7 +519,7 @@ static void dma_chan_put(struct dma_chan *chan) /* This channel is not in use anymore, drop the device ref */ if (!chan->client_count) dma_device_put(chan->device); - module_put(dma_chan_to_owner(chan)); + module_put(owner); } enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie) -- 2.53.0