thp: avoid race on multiple parallel page faults to the same page
authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Wed, 12 Dec 2012 21:51:14 +0000 (13:51 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 13 Dec 2012 01:38:32 +0000 (17:38 -0800)
commit3ea41e6210fea3b234b6cb3e9443e75975850bbf
tree1c8490271a6cffa9b43858e0f29d6ddab0122fac
parent79da5407eeadc740fbf4b45d6df7d7f8e6adaf2c
thp: avoid race on multiple parallel page faults to the same page

pmd value is stable only with mm->page_table_lock taken. After taking
the lock we need to check that nobody modified the pmd before changing it.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Reviewed-by: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/huge_memory.c