tree c6fba8d5a532ecfa53dc97a3841d13d972964854
parent df69a60dc6afc2936d79054d30b481c1fd9720e5
author David Gibson <david@gibson.dropbear.id.au> 1133321672 -0800
committer Linus Torvalds <torvalds@g5.osdl.org> 1133322423 -0800

[PATCH] Fix crash when ptrace poking hugepage areas

set_page_dirty() will not cope with being handed a page * which is part of
a compound page, but not the master page in that compound page.  This case
can occur via access_process_vm() if you attemp to write to another
process's hugepage memory area using ptrace() (causing an oops or hang).

This patch fixes the bug by only calling set_page_dirty() from
access_process_vm() if the page is not a compound page.  We already use a
similar fix in bio_set_pages_dirty() for the case of direct io to
hugepages.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>