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.

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+ --- 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);