From: Mike Christie <mchristi@xxxxxxxxxx> [ Upstream commit 887e975c4172d0d5670c39ead2f18ba1e4ec8133 ] Fix bug added with the patch: commit 8f3ea35929a0806ad1397db99a89ffee0140822a Author: Josef Bacik <josef@xxxxxxxxxxxxxx> Date: Mon Jul 16 12:11:35 2018 -0400 nbd: handle unexpected replies better where if the timeout handler runs when the completion path is and we fail to grab the mutex in the timeout handler we will leave a config reference and cannot free the config later. Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> Signed-off-by: Mike Christie <mchristi@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/block/nbd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index e21d2ded732b7..a69a90ad92088 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -357,8 +357,10 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, } config = nbd->config; - if (!mutex_trylock(&cmd->lock)) + if (!mutex_trylock(&cmd->lock)) { + nbd_config_put(nbd); return BLK_EH_RESET_TIMER; + } if (config->num_connections > 1) { dev_err_ratelimited(nbd_to_dev(nbd), -- 2.20.1