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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 F2638C64E90 for ; Tue, 1 Dec 2020 16:39:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8290A20644 for ; Tue, 1 Dec 2020 16:39:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727397AbgLAQjC (ORCPT ); Tue, 1 Dec 2020 11:39:02 -0500 Received: from mx2.suse.de ([195.135.220.15]:49908 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727175AbgLAQjC (ORCPT ); Tue, 1 Dec 2020 11:39:02 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 32D89AE93; Tue, 1 Dec 2020 16:38:20 +0000 (UTC) To: Yi Li Cc: yilikernel@gmail.com, kent.overstreet@gmail.com, linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org, Guo Chao References: <20201130112137.587437-1-yili@winhong.com> From: Coly Li Subject: Re: [PATCH] bcache: fix panic due to cache_set is null Message-ID: Date: Wed, 2 Dec 2020 00:38:13 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20201130112137.587437-1-yili@winhong.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/30/20 7:21 PM, Yi Li wrote: > bcache_device_detach will release the cache_set after hotunplug cache > disk. update_writeback_rate should check validate of cache_set. > I see the kernel is 4.4.0+10, do you try the the v5.9 kernel ? I don't see your kernel code, it is not easy to response. Thanks. Coly LI > 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, >