From: Mel Gorman Date: Wed, 5 Dec 2012 22:01:41 +0000 (-0800) Subject: tmpfs: fix shared mempolicy leak X-Git-Tag: v3.2.36~142 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c6dc8bee909fd3b11d9f591165bd614e3c3ab99d;p=pandora-kernel.git tmpfs: fix shared mempolicy leak commit 18a2f371f5edf41810f6469cb9be39931ef9deb9 upstream. This fixes a regression in 3.7-rc, which has since gone into stable. Commit 00442ad04a5e ("mempolicy: fix a memory corruption by refcount imbalance in alloc_pages_vma()") changed get_vma_policy() to raise the refcount on a shmem shared mempolicy; whereas shmem_alloc_page() went on expecting alloc_page_vma() to drop the refcount it had acquired. This deserves a rework: but for now fix the leak in shmem_alloc_page(). Hugh: shmem_swapin() did not need a fix, but surely it's clearer to use the same refcounting there as in shmem_alloc_page(), delete its onstack mempolicy, and the strange mpol_cond_copy() and __mpol_cond_copy() - those were invented to let swapin_readahead() make an unknown number of calls to alloc_pages_vma() with one mempolicy; but since 00442ad04a5e, alloc_pages_vma() has kept refcount in balance, so now no problem. Reported-and-tested-by: Tommi Rantala Signed-off-by: Mel Gorman Signed-off-by: Hugh Dickins Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed