On 2018/8/23 2:02 AM, Coly Li wrote:

From: Shan Hai shan.hai@oracle.com

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 shan.hai@oracle.com Signed-off-by: Coly Li colyli@suse.de Tested-by: Shenghui Wang shhuiw@foxmail.com 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);