From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AFADC64E8A for ; Mon, 30 Nov 2020 11:28:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7DEB20855 for ; Mon, 30 Nov 2020 11:28:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728610AbgK3L1o (ORCPT ); Mon, 30 Nov 2020 06:27:44 -0500 Received: from regular1.263xmail.com ([211.150.70.206]:50050 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726991AbgK3L1o (ORCPT ); Mon, 30 Nov 2020 06:27:44 -0500 Received: from localhost (unknown [192.168.167.32]) by regular1.263xmail.com (Postfix) with ESMTP id A57781A98; Mon, 30 Nov 2020 19:21:46 +0800 (CST) X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-ADDR-CHECKED4: 1 X-ANTISPAM-LEVEL: 2 X-SKE-CHECKED: 1 X-ABS-CHECKED: 1 Received: from localhost.localdomain (unknown [14.18.236.70]) by smtp.263.net (postfix) whith ESMTP id P26670T140451934750464S1606735299812191_; Mon, 30 Nov 2020 19:21:46 +0800 (CST) X-IP-DOMAINF: 1 X-UNIQUE-TAG: <609705c7df649c7f57edb97859403f48> X-RL-SENDER: yili@winhong.com X-SENDER: yili@winhong.com X-LOGIN-NAME: yili@winhong.com X-FST-TO: colyli@suse.de X-SENDER-IP: 14.18.236.70 X-ATTACHMENT-NUM: 0 X-System-Flag: 0 From: Yi Li To: colyli@suse.de Cc: yilikernel@gmail.com, kent.overstreet@gmail.com, linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org, Yi Li , Guo Chao Subject: [PATCH] bcache: fix panic due to cache_set is null Date: Mon, 30 Nov 2020 19:21:37 +0800 Message-Id: <20201130112137.587437-1-yili@winhong.com> X-Mailer: git-send-email 2.25.3 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org bcache_device_detach will release the cache_set after hotunplug cache disk. update_writeback_rate should check validate of cache_set. IP: [] update_writeback_rate+0x59/0x3a0 [bcache] PGD 879620067 PUD 8755d3067 PMD 0 Oops: 0000 [#1] SMP CPU: 8 PID: 1005702 Comm: kworker/8:0 Tainted: G 4.4.0+10 #1 Hardware name: Intel BIOS SE5C610.86B.01.01.0021.032120170601 03/21/2017 Workqueue: events update_writeback_rate [bcache] task: ffff8808786f3800 ti: ffff88077082c000 task.ti: ffff88077082c000 RIP: e030:[] update_writeback_rate+0x59/0x3a0 [bcache] RSP: e02b:ffff88077082fde0 EFLAGS: 00010202 RAX: 0000000000000018 RBX: ffff8808047f0b08 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffff88088170dab8 RDI: ffff88088170dab8 RBP: ffff88077082fe18 R08: 000000000000000a R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000017bc8 R12: 0000000000000000 R13: ffff8808047f0000 R14: 0000000000000200 R15: ffff8808047f0b08 FS: 00007f157b6d6700(0000) GS:ffff880881700000(0000) knlGS:0000000000000000 CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000368 CR3: 0000000875c05000 CR4: 0000000000040660 Stack: 0000000000000001 0000000000007ff0 ffff88085ff600c0 ffff880881714e80 ffff880881719500 0000000000000200 ffff8808047f0b08 ffff88077082fe60 ffffffff81088c0c 0000000081714e80 0000000000000000 ffff880881714e80 Call Trace: [] process_one_work+0x1fc/0x3b0 [] worker_thread+0x2a5/0x470 [] ? __schedule+0x648/0x870 [] ? rescuer_thread+0x300/0x300 [] kthread+0xd5/0xe0 [] ? kthread_stop+0x110/0x110 [] ret_from_fork+0x3f/0x70 [] ? kthread_stop+0x110/0x110 Reported-by: Guo Chao Signed-off-by: Guo Chao Signed-off-by: Yi Li --- drivers/md/bcache/writeback.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c index 3c74996978da..186c4c6e1607 100644 --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -175,7 +175,15 @@ static void update_writeback_rate(struct work_struct *work) struct cached_dev *dc = container_of(to_delayed_work(work), struct cached_dev, writeback_rate_update); - struct cache_set *c = dc->disk.c; + struct cache_set *c = NULL; + + mutex_lock(&bch_register_lock); + c = dc->disk.c; + + if (c == NULL) { + mutex_unlock(&bch_register_lock); + return; + } /* * should check BCACHE_DEV_RATE_DW_RUNNING before calling @@ -194,6 +202,7 @@ static void update_writeback_rate(struct work_struct *work) clear_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags); /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */ smp_mb__after_atomic(); + mutex_unlock(&bch_register_lock); return; } @@ -230,6 +239,7 @@ static void update_writeback_rate(struct work_struct *work) clear_bit(BCACHE_DEV_RATE_DW_RUNNING, &dc->disk.flags); /* paired with where BCACHE_DEV_RATE_DW_RUNNING is tested */ smp_mb__after_atomic(); + mutex_unlock(&bch_register_lock); } static unsigned int writeback_delay(struct cached_dev *dc, -- 2.25.3