Commit 8970a63e authored by Yisheng Xie's avatar Yisheng Xie Committed by Linus Torvalds

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: fc36b8d3 ("mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy")
Signed-off-by: default avatarYisheng Xie <xieyisheng1@huawei.com>
Reported-by: default avatarAlexander Potapenko <glider@google.com>
Tested-by: default avatarAlexander Potapenko <glider@google.com>
Reviewed-by: default avatarAndrew 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3215b9d5
...@@ -2124,6 +2124,9 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b) ...@@ -2124,6 +2124,9 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
case MPOL_INTERLEAVE: case MPOL_INTERLEAVE:
return !!nodes_equal(a->v.nodes, b->v.nodes); return !!nodes_equal(a->v.nodes, b->v.nodes);
case MPOL_PREFERRED: 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; return a->v.preferred_node == b->v.preferred_node;
default: default:
BUG(); BUG();
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment