CVE request: kernel: splice: fix bad unlock_page() in error case

[Eugene Teo <eteo () redhat com>]

Hi Steve,

This bug requires a CVE name. Please allocate one.

This upstream commit addressed a user triggerable DoS:
6a860c979b35469e4d77da781a96bdb2ca05ae64

Summary:
[PATCH] splice: fix bad unlock_page() in error case

If add_to_page_cache_lru() fails, the page will not be locked. But
splice jumps to an error path that does a page release and unlock,
causing a BUG() in unlock_page().

Reproducer:
http://lkml.org/lkml/2007/7/30/448
(different issue, but same reproducer)

References:
http://lkml.org/lkml/2007/7/20/168
https://bugzilla.redhat.com/show_bug.cgi?id=462434

Thanks, Eugene
-- 
Eugene Teo / Red Hat Security Response Team