diff options
author | Vlastimil Babka <[email protected]> | 2017-01-24 15:18:18 -0800 |
---|---|---|
committer | Linus Torvalds <[email protected]> | 2017-01-24 16:26:14 -0800 |
commit | d51e9894d27492783fc6d1b489070b4ba66ce969 (patch) | |
tree | 621d6cdd62b6cb6a97d5fb97b8dc2f1eca3197c5 | |
parent | dd040b6f6d5630202e185399a2ff7ab356ed469c (diff) |
mm/mempolicy.c: do not put mempolicy before using its nodemask
Since commit be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to
alloc_pages_vma") alloc_pages_vma() can potentially free a mempolicy by
mpol_cond_put() before accessing the embedded nodemask by
__alloc_pages_nodemask(). The commit log says it's so "we can use a
single exit path within the function" but that's clearly wrong. We can
still do that when doing mpol_cond_put() after the allocation attempt.
Make sure the mempolicy is not freed prematurely, otherwise
__alloc_pages_nodemask() can end up using a bogus nodemask, which could
lead e.g. to premature OOM.
Fixes: be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to alloc_pages_vma")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: <[email protected]> [4.0+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
-rw-r--r-- | mm/mempolicy.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 2e346645eb80..1e7873e40c9a 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2017,8 +2017,8 @@ retry_cpuset: nmask = policy_nodemask(gfp, pol); zl = policy_zonelist(gfp, pol, node); - mpol_cond_put(pol); page = __alloc_pages_nodemask(gfp, order, zl, nmask); + mpol_cond_put(pol); out: if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) goto retry_cpuset; |