[PATCH AUTOSEL 4.14 47/89] nbd: add missing config put

* [PATCH AUTOSEL 4.14 47/89] nbd: add missing config put
       [not found] <20190922185717.3412-1-sashal@kernel.org>
@ 2019-09-22 18:56 ` Sasha Levin
  0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2019-09-22 18:56 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Mike Christie, Josef Bacik, Jens Axboe, Sasha Levin, linux-block, nbd

From: Mike Christie <mchristi@redhat.com>

[ 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>
---
 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 b77e9281c039d..e4b049f281f50 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -340,8 +340,10 @@ 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


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