Commit 839ec545 authored by Paul Menage's avatar Paul Menage Committed by Linus Torvalds

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: default avatarPaul Menage <menage@google.com>
Tested-by: default avatarSerge Hallyn <serue@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 804b3c28
......@@ -1115,8 +1115,10 @@ static void cgroup_kill_sb(struct super_block *sb) {
}
write_unlock(&css_set_lock);
list_del(&root->root_list);
root_count--;
if (!list_empty(&root->root_list)) {
list_del(&root->root_list);
root_count--;
}
mutex_unlock(&cgroup_mutex);
......
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