On Wed, Oct 17, 2012 at 08:55:49PM -0700, Hugh Dickins wrote: > On Wed, 17 Oct 2012, David Rientjes wrote: > > > 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 <fengguang...@intel.com> > > Signed-off-by: David Rientjes <rient...@google.com> > > Acked-by: Hugh Dickins <hu...@google.com> > > Thank you both: a fine example of the danger of uninitialized_var()!
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