From: Mike Christie <mchristi@redhat.com>
Date: Tue, 13 Aug 2019 16:39:51 +0000 (-0500)
Subject: nbd: add missing config put
X-Git-Tag: v5.2.19~191
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=8e8821e511803d07375ffe20a326b3baaac87f64;p=users%2Fdwmw2%2Flinux.git

nbd: add missing config put

[ Upstream commit 887e975c4172d0d5670c39ead2f18ba1e4ec8133 ]

Fix bug added with the patch:

commit 8f3ea35929a0806ad1397db99a89ffee0140822a
Author: Josef Bacik <josef@toxicpanda.com>
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@toxicpanda.com>
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 57aebc6e1c288..5d5e52c6509ce 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -355,8 +355,10 @@ 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),