linux-kernel - [PATCH 3.18 53/90] dm: remove duplicate dm_get_live_table() in __dm

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Message-Id: <20181119162629.402065358@linuxfoundation.org>
Date:   Mon, 19 Nov 2018 17:29:35 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sasha Levin <sashal@...nel.org>,
        Corey Wright <undefined@...ox.com>
Subject: [PATCH 3.18 53/90] dm: remove duplicate dm_get_live_table() in __dm_destroy()

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Corey Wright <undefined@...ox.com>

[3.18.y only, to fix a previous patch]

__dm_destroy() takes io_barrier SRCU lock (dm_get_live_table) twice
which leads to a deadlock.  Remove taking lock before holding
suspend_lock to prevent a different potential deadlock.

Signed-off-by: Corey Wright <undefined@...ox.com>
Fixes: e1db66a5fdcc ("dm: fix AB-BA deadlock in __dm_destroy()")
Cc: Sasha Levin <sashal@...nel.org>
---
 drivers/md/dm.c |    1 -
 1 file changed, 1 deletion(-)

--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2589,7 +2589,6 @@ static void __dm_destroy(struct mapped_d
 	might_sleep();
 
 	spin_lock(&_minor_lock);
-	map = dm_get_live_table(md, &srcu_idx);
 	idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
 	set_bit(DMF_FREEING, &md->flags);
 	spin_unlock(&_minor_lock);