From mboxrd@z Thu Jan 1 00:00:00 1970 From: Coly Li Subject: Re: [PATCH v2] bcache: release dc->writeback_lock properly in bch_writeback_thread() Date: Thu, 23 Aug 2018 02:07:55 +0800 Message-ID: References: <20180822180256.15600-1-colyli@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180822180256.15600-1-colyli@suse.de> Content-Language: en-US Sender: stable-owner@vger.kernel.org To: axboe@kernel.dk Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, Shan Hai , stable@vger.kernel.org List-Id: linux-bcache@vger.kernel.org On 2018/8/23 2:02 AM, Coly Li wrote: > From: Shan Hai > > The writeback thread would exit with a lock held when the cache device is > detached via sysfs interface, fix it by releasing the held lock before exiting > the while-loop. > > Fixes: fadd94e05c02 (bcache: quit dc->writeback_thread when BCACHE_DEV_DETACHING is set) > Signed-off-by: Shan Hai > Signed-off-by: Coly Li > Tested-by: Shenghui Wang > Cc: stable@vger.kernel.org #4.17+ > --- > Changelog: > v2: add Fixes tag by Coly Li. > v1: initial patch from Shan Hai. Hi Jens, Please pick this patch for your next pull request. The change from Shan Hai fixes a real issue which is reported and lately verified by Shenghui Wang. Thanks in advance. Coly Li > > drivers/md/bcache/writeback.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c > index 6be05bd7ca67..08c3a9f9676c 100644 > --- a/drivers/md/bcache/writeback.c > +++ b/drivers/md/bcache/writeback.c > @@ -685,8 +685,10 @@ static int bch_writeback_thread(void *arg) > * data on cache. BCACHE_DEV_DETACHING flag is set in > * bch_cached_dev_detach(). > */ > - if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) > + if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags)) { > + up_write(&dc->writeback_lock); > break; > + } > } > > up_write(&dc->writeback_lock); >