]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm: fix slab->page _count corruption when using slub
authorPravin B Shelar <pshelar@nicira.com>
Wed, 20 Jun 2012 19:52:56 +0000 (12:52 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 20 Jun 2012 21:39:35 +0000 (14:39 -0700)
commitabca7c4965845924f65d40e0aa1092bdd895e314
tree18d908b58243b6f46cadfa4515d6370299c88d3f
parent485802a6c524e62b5924849dd727ddbb1497cc71
mm: fix slab->page _count corruption when using slub

On arches that do not support this_cpu_cmpxchg_double() slab_lock is used
to do atomic cmpxchg() on double word which contains page->_count.  The
page count can be changed from get_page() or put_page() without taking
slab_lock.  That corrupts page counter.

Fix it by moving page->_count out of cmpxchg_double data.  So that slub
does no change it while updating slub meta-data in struct page.

[akpm@linux-foundation.org: use standard comment layout, tweak comment text]
Reported-by: Amey Bhide <abhide@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/mm_types.h