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 3CFFA2BD012; Wed, 4 Feb 2026 15:32:04 +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=1770219124; cv=none; b=LQSNAEzGLbhQNc8eTDms5KqQs9dzsRh1UvDQHdSbOskYna+N+FCI4f4okuhfZ0JS7HpsgRjm2S1S6vD8TunWGaBvD12iFaT04WAjDfGKH5XmGXVivF+/vqL4OGZGLA1t4JSAjCdyRZZm69w0CS5S1evQ4T4fjXnrO7rVvlySx0w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770219124; c=relaxed/simple; bh=xTQUe9O9/waiirkcEnwElWO0vvV1ecS2CcFA6B0QMQ4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EqSf2cJEefL7eYmLm9M50D9rGM8Ywwm3oT2GvD0RJjEUOJmrQqb/vIUOem8IbatDzUqBHBiciM+Es5u4F4ZoCIy6LPOmz4+gWdqHge4f9jKTv3m/PXm/soknWfVxdjVmudBv+o3N4ef/cG5O2+a21nmqdGlf4xGFpZSlFv8k9xI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pq7kJQ6V; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pq7kJQ6V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE3B7C4CEF7; Wed, 4 Feb 2026 15:32:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1770219124; bh=xTQUe9O9/waiirkcEnwElWO0vvV1ecS2CcFA6B0QMQ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pq7kJQ6V8kZDTEcAvLEtiab7gaUdBHTctR3XSFUNNL+J33ezGIQ3gegMeAvthS3jq f/Q6/dWtAFaf8dA5muDgUDSByP01yQFDHvzIwRvW7W2YK/Bikp2yJazwc3CUdPxMGw FaZr6CfB0lTHPikOxvUIGK2isIP0Te/Az0JVwiJg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dmitry Bogdanov , Guangwu Zhang , Christoph Hellwig , Ming Lei , Keith Busch Subject: [PATCH 6.18 075/122] nvmet: fix race in nvmet_bio_done() leading to NULL pointer dereference Date: Wed, 4 Feb 2026 15:40:57 +0100 Message-ID: <20260204143854.551210194@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260204143851.857060534@linuxfoundation.org> References: <20260204143851.857060534@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei commit 0fcee2cfc4b2e16e62ff8e0cc2cd8dd24efad65e upstream. There is a race condition in nvmet_bio_done() that can cause a NULL pointer dereference in blk_cgroup_bio_start(): 1. nvmet_bio_done() is called when a bio completes 2. nvmet_req_complete() is called, which invokes req->ops->queue_response(req) 3. The queue_response callback can re-queue and re-submit the same request 4. The re-submission reuses the same inline_bio from nvmet_req 5. Meanwhile, nvmet_req_bio_put() (called after nvmet_req_complete) invokes bio_uninit() for inline_bio, which sets bio->bi_blkg to NULL 6. The re-submitted bio enters submit_bio_noacct_nocheck() 7. blk_cgroup_bio_start() dereferences bio->bi_blkg, causing a crash: BUG: kernel NULL pointer dereference, address: 0000000000000028 #PF: supervisor read access in kernel mode RIP: 0010:blk_cgroup_bio_start+0x10/0xd0 Call Trace: submit_bio_noacct_nocheck+0x44/0x250 nvmet_bdev_execute_rw+0x254/0x370 [nvmet] process_one_work+0x193/0x3c0 worker_thread+0x281/0x3a0 Fix this by reordering nvmet_bio_done() to call nvmet_req_bio_put() BEFORE nvmet_req_complete(). This ensures the bio is cleaned up before the request can be re-submitted, preventing the race condition. Fixes: 190f4c2c863a ("nvmet: fix memory leak of bio integrity") Cc: Dmitry Bogdanov Cc: stable@vger.kernel.org Cc: Guangwu Zhang Link: http://www.mail-archive.com/debian-kernel@lists.debian.org/msg146238.html Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Keith Busch Signed-off-by: Greg Kroah-Hartman --- drivers/nvme/target/io-cmd-bdev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/nvme/target/io-cmd-bdev.c +++ b/drivers/nvme/target/io-cmd-bdev.c @@ -180,9 +180,10 @@ u16 blk_to_nvme_status(struct nvmet_req static void nvmet_bio_done(struct bio *bio) { struct nvmet_req *req = bio->bi_private; + blk_status_t blk_status = bio->bi_status; - nvmet_req_complete(req, blk_to_nvme_status(req, bio->bi_status)); nvmet_req_bio_put(req, bio); + nvmet_req_complete(req, blk_to_nvme_status(req, blk_status)); } #ifdef CONFIG_BLK_DEV_INTEGRITY