From nobody Wed Sep 17 06:40:18 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C37C1C4332F for ; Thu, 22 Dec 2022 01:57:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234910AbiLVB5y (ORCPT ); Wed, 21 Dec 2022 20:57:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229601AbiLVB5v (ORCPT ); Wed, 21 Dec 2022 20:57:51 -0500 Received: from smtp.cecloud.com (unknown [106.39.185.58]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4A0A624BE8 for ; Wed, 21 Dec 2022 17:57:49 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by smtp.cecloud.com (Postfix) with ESMTP id 0D84517E0205; Thu, 22 Dec 2022 09:57:42 +0800 (CST) X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-ANTISPAM-LEVEL: 2 X-ABS-CHECKED: 0 Received: from localhost.localdomain (unknown [111.48.58.13]) by smtp.cecloud.com (postfix) whith ESMTP id P2473742T281457543016816S1671674261238154_; Thu, 22 Dec 2022 09:57:42 +0800 (CST) X-IP-DOMAINF: 1 X-UNIQUE-TAG: <7b05fc6580268c758c9c8fe1f738483b> X-RL-SENDER: zhangyanjun@cestc.cn X-SENDER: zhangyanjun@cestc.cn X-LOGIN-NAME: zhangyanjun@cestc.cn X-FST-TO: hch@lst.de X-RCPT-COUNT: 7 X-SENDER-IP: 111.48.58.13 X-ATTACHMENT-NUM: 0 X-System-Flag: 0 From: zhangyanjun@cestc.cn To: hch@lst.de, sagi@grimberg.me, kbusch@kernel.org, axboe@fb.com Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Yanjun Zhang Subject: [PATCH v3] nvme: fix multipath crash caused by flush request when blktrace is enabled Date: Thu, 22 Dec 2022 09:57:21 +0800 Message-Id: <20221222015721.76241-1-zhangyanjun@cestc.cn> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yanjun Zhang The flush request initialized by blk_kick_flush has NULL bio, and it may be dealt with nvme_end_req during io completion. When blktrace is enabled, nvme_trace_bio_complete with multipath activated trying to access NULL pointer bio from flush request results in the following crash: [ 2517.831677] BUG: kernel NULL pointer dereference, address: 0000000000000= 01a [ 2517.835213] #PF: supervisor read access in kernel mode [ 2517.838724] #PF: error_code(0x0000) - not-present page [ 2517.842222] PGD 7b2d51067 P4D 0 [ 2517.845684] Oops: 0000 [#1] SMP NOPTI [ 2517.849125] CPU: 2 PID: 732 Comm: kworker/2:1H Kdump: loaded Tainted: G = S 5.15.67-0.cl9.x86_64 #1 [ 2517.852723] Hardware name: XFUSION 2288H V6/BC13MBSBC, BIOS 1.13 07/27/2= 022 [ 2517.856358] Workqueue: nvme_tcp_wq nvme_tcp_io_work [nvme_tcp] [ 2517.859993] RIP: 0010:blk_add_trace_bio_complete+0x6/0x30 [ 2517.863628] Code: 1f 44 00 00 48 8b 46 08 31 c9 ba 04 00 10 00 48 8b 80 = 50 03 00 00 48 8b 78 50 e9 e5 fe ff ff 0f 1f 44 00 00 41 54 49 89 f4 55 <0f= > b6 7a 1a 48 89 d5 e8 3e 1c 2b 00 48 89 ee 4c 89 e7 5d 89 c1 ba [ 2517.871269] RSP: 0018:ff7f6a008d9dbcd0 EFLAGS: 00010286 [ 2517.875081] RAX: ff3d5b4be00b1d50 RBX: 0000000002040002 RCX: ff3d5b0a270= f2000 [ 2517.878966] RDX: 0000000000000000 RSI: ff3d5b0b021fb9f8 RDI: 00000000000= 00000 [ 2517.882849] RBP: ff3d5b0b96a6fa00 R08: 0000000000000001 R09: 00000000000= 00000 [ 2517.886718] R10: 000000000000000c R11: 000000000000000c R12: ff3d5b0b021= fb9f8 [ 2517.890575] R13: 0000000002000000 R14: ff3d5b0b021fb1b0 R15: 00000000000= 00018 [ 2517.894434] FS: 0000000000000000(0000) GS:ff3d5b42bfc80000(0000) knlGS:= 0000000000000000 [ 2517.898299] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2517.902157] CR2: 000000000000001a CR3: 00000004f023e005 CR4: 00000000007= 71ee0 [ 2517.906053] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000= 00000 [ 2517.909930] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 00000000000= 00400 [ 2517.913761] PKRU: 55555554 [ 2517.917558] Call Trace: [ 2517.921294] [ 2517.924982] nvme_complete_rq+0x1c3/0x1e0 [nvme_core] [ 2517.928715] nvme_tcp_recv_pdu+0x4d7/0x540 [nvme_tcp] [ 2517.932442] nvme_tcp_recv_skb+0x4f/0x240 [nvme_tcp] [ 2517.936137] ? nvme_tcp_recv_pdu+0x540/0x540 [nvme_tcp] [ 2517.939830] tcp_read_sock+0x9c/0x260 [ 2517.943486] nvme_tcp_try_recv+0x65/0xa0 [nvme_tcp] [ 2517.947173] nvme_tcp_io_work+0x64/0x90 [nvme_tcp] [ 2517.950834] process_one_work+0x1e8/0x390 [ 2517.954473] worker_thread+0x53/0x3c0 [ 2517.958069] ? process_one_work+0x390/0x390 [ 2517.961655] kthread+0x10c/0x130 [ 2517.965211] ? set_kthread_struct+0x40/0x40 [ 2517.968760] ret_from_fork+0x1f/0x30 [ 2517.972285] To avoid this situation, add a NULL check for req->bio before calling trace_block_bio_complete. Signed-off-by: Yanjun Zhang --- drivers/nvme/host/nvme.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index a29877217..41f87d970 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -888,7 +888,7 @@ static inline void nvme_trace_bio_complete(struct reque= st *req) { struct nvme_ns *ns =3D req->q->queuedata; =20 - if (req->cmd_flags & REQ_NVME_MPATH) + if ((req->cmd_flags & REQ_NVME_MPATH) && req->bio) trace_block_bio_complete(ns->head->disk->queue, req->bio); } =20 --=20 2.31.1