From: David Rientjes Date: Thu, 18 Oct 2012 03:41:15 +0000 (-0700) Subject: fs, xattr: fix bug when removing a name not in xattr list X-Git-Tag: v3.7-rc2~26 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=43385846968b082bb6c174e8b17479e5123b8d73;p=platform%2Fkernel%2Flinux-3.10.git fs, xattr: fix bug when removing a name not in xattr list Commit 38f38657444d ("xattr: extract simple_xattr code from tmpfs") moved some code from tmpfs but introduced a subtle bug along the way. If the name passed to simple_xattr_remove() does not exist in the list of xattrs, then it is possible to call kfree(new_xattr) when new_xattr is actually initialized to itself on the stack via uninitialized_var(). This causes a BUG() since the memory was not allocated via the slab allocator and was not bypassed through to the page allocator because it was too large. Initialize the local variable to NULL so the kfree() never takes place. Reported-by: Fengguang Wu Signed-off-by: David Rientjes Acked-by: Hugh Dickins Acked-by: Aristeu Rozanski Signed-off-by: Linus Torvalds --- diff --git a/fs/xattr.c b/fs/xattr.c index e164ddd..e21c119 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -846,7 +846,7 @@ static int __simple_xattr_set(struct simple_xattrs *xattrs, const char *name, const void *value, size_t size, int flags) { struct simple_xattr *xattr; - struct simple_xattr *uninitialized_var(new_xattr); + struct simple_xattr *new_xattr = NULL; int err = 0; /* value == NULL means remove */