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authorYisheng Xie <xieyisheng1@huawei.com>2018-03-22 16:17:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-03-22 17:07:01 -0700
commit8970a63e965b43288c4f5f40efbc2bbf80de7f16 (patch)
tree5fbccafe8068d97d24f9cb26354cbfe9c0e6b3e1
parent3215b9d57a2c75c4305a3956ca303d7004485200 (diff)
downloadlinux-stericsson-8970a63e965b43288c4f5f40efbc2bbf80de7f16.tar.gz
mm/mempolicy.c: avoid use uninitialized preferred_node
Alexander reported a use of uninitialized memory in __mpol_equal(), which is caused by incorrect use of preferred_node. When mempolicy in mode MPOL_PREFERRED with flags MPOL_F_LOCAL, it uses numa_node_id() instead of preferred_node, however, __mpol_equal() uses preferred_node without checking whether it is MPOL_F_LOCAL or not. [akpm@linux-foundation.org: slight comment tweak] Link: http://lkml.kernel.org/r/4ebee1c2-57f6-bcb8-0e2d-1833d1ee0bb7@huawei.com Fixes: fc36b8d3d819 ("mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy") Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Reported-by: Alexander Potapenko <glider@google.com> Tested-by: Alexander Potapenko <glider@google.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mempolicy.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d879f1d8a44a..32cba0332787 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2124,6 +2124,9 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
case MPOL_INTERLEAVE:
return !!nodes_equal(a->v.nodes, b->v.nodes);
case MPOL_PREFERRED:
+ /* a's ->flags is the same as b's */
+ if (a->flags & MPOL_F_LOCAL)
+ return true;
return a->v.preferred_node == b->v.preferred_node;
default:
BUG();