linux-kernel - [07/35] PM: Free memory bitmaps if opening /dev/snapshot fails

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Message-Id: <20110708225119.510053976@clark.kroah.org>
Date:	Fri, 08 Jul 2011 15:49:56 -0700
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Michal Kubecek <mkubecek@...e.cz>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: [07/35] PM: Free memory bitmaps if opening /dev/snapshot fails

2.6.32-longterm review patch.  If anyone has any objections, please let us know.

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

From: Michal Kubecek <mkubecek@...e.cz>

commit 8440f4b19494467883f8541b7aa28c7bbf6ac92b upstream.

When opening /dev/snapshot device, snapshot_open() creates memory
bitmaps which are freed in snapshot_release(). But if any of the
callbacks called by pm_notifier_call_chain() returns NOTIFY_BAD, open()
fails, snapshot_release() is never called and bitmaps are not freed.
Next attempt to open /dev/snapshot then triggers BUG_ON() check in
create_basic_memory_bitmaps(). This happens e.g. when vmwatchdog module
is active on s390x.

Signed-off-by: Michal Kubecek <mkubecek@...e.cz>
Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 kernel/power/user.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -113,8 +113,10 @@ static int snapshot_open(struct inode *i
 		if (error)
 			pm_notifier_call_chain(PM_POST_RESTORE);
 	}
-	if (error)
+	if (error) {
+		free_basic_memory_bitmaps();
 		atomic_inc(&snapshot_device_available);
+	}
 	data->frozen = 0;
 	data->ready = 0;
 	data->platform_support = 0;

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