Commit 839ec545 authored Jan 29, 2009 by Paul Menage Committed by Linus Torvalds Jan 29, 2009

cgroup: fix root_count when mount fails due to busy subsystem



root_count was being incremented in cgroup_get_sb() after all error
checking was complete, but decremented in cgroup_kill_sb(), which can be
called on a superblock that we gave up on due to an error.  This patch
changes cgroup_kill_sb() to only decrement root_count if the root was
previously linked into the list of roots.

Signed-off-by: Paul Menage <menage@google.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 804b3c28

kernel/cgroup.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1115,8 +1115,10 @@ static void cgroup_kill_sb(struct super_block *sb) {
	}		}
	write_unlock(&css_set_lock);		write_unlock(&css_set_lock);

			if (!list_empty(&root->root_list)) {
	list_del(&root->root_list);		list_del(&root->root_list);
	root_count--;		root_count--;
			}

	mutex_unlock(&cgroup_mutex);		mutex_unlock(&cgroup_mutex);

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