From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jia-Ju Bai Subject: Re: [PATCH] bcache: Fix a sleep-in-atomic bug Date: Wed, 31 May 2017 16:31:18 +0800 Message-ID: <592E7F56.7050400@163.com> References: <1496215420-15819-1-git-send-email-baijiaju1990@163.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1496215420-15819-1-git-send-email-baijiaju1990@163.com> Sender: linux-kernel-owner@vger.kernel.org To: Jia-Ju Bai Cc: kent.overstreet@gmail.com, shli@kernel.org, axboe@fb.com, mchristi@redhat.com, git@linux.ewheeler.net, colyli@suse.de, akpm@linux-foundation.org, wangyijing@huawei.com, mingo@kernel.org, mhocko@suse.com, linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-raid.ids On 05/31/2017 03:23 PM, Jia-Ju Bai wrote: > The driver may sleep under a spin lock, and the function call path is: > journal_wait_for_write (acquire the lock by spin_lock) > closure_sync > schedule --> may sleep > > To fix it, the lock is released before "closure_sync", and the lock is > acquired again after this function. > > Signed-off-by: Jia-Ju Bai > --- > drivers/md/bcache/journal.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c > index 1198e53..ad47c36 100644 > --- a/drivers/md/bcache/journal.c > +++ b/drivers/md/bcache/journal.c > @@ -724,6 +724,7 @@ static struct journal_write *journal_wait_for_write(struct cache_set *c, > btree_flush_write(c); > } > > + spin_unlock(&c->journal.lock); > closure_sync(&cl); > spin_lock(&c->journal.lock); > wait = true; Sorry, my patch is not correct, and it will cause double unlock. Please ignore my patch. Jia-Ju Bai