[PATCH 4.5 137/238] bcache: fix cache_set_flush() NULL pointer dereference on OOM

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.5 137/238] bcache: fix cache_set_flush() NULL pointer dereference on OOM
Date	2016-04-10 22:40 +0200
Message-ID	<rmujj-2ia-87@gated-at.bofh.it> (permalink)
References	<rmsr7-Nr-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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

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

From: Eric Wheeler <git@linux.ewheeler.net>

commit f8b11260a445169989d01df75d35af0f56178f95 upstream.

When bch_cache_set_alloc() fails to kzalloc the cache_set, the
asyncronous closure handling tries to dereference a cache_set that
hadn't yet been allocated inside of cache_set_flush() which is called
by __cache_set_unregister() during cleanup.  This appears to happen only
during an OOM condition on bcache_register.

Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/bcache/super.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1373,6 +1373,9 @@ static void cache_set_flush(struct closu
 	struct btree *b;
 	unsigned i;
 
+	if (!c)
+		closure_return(cl);
+
 	bch_cache_accounting_destroy(&c->accounting);
 
 	kobject_put(&c->internal);

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[PATCH 4.5 137/238] bcache: fix cache_set_flush() NULL pointer dereference on OOM Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 22:40 +0200

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