4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Yisheng Xie <[email protected]> [ Upstream commit 8970a63e965b43288c4f5f40efbc2bbf80de7f16 ] 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. [[email protected]: slight comment tweak] Link: http://lkml.kernel.org/r/[email protected] Fixes: fc36b8d3d819 ("mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy") Signed-off-by: Yisheng Xie <[email protected]> Reported-by: Alexander Potapenko <[email protected]> Tested-by: Alexander Potapenko <[email protected]> Reviewed-by: Andrew Morton <[email protected]> Cc: Dmitriy Vyukov <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Michal Hocko <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/mempolicy.c | 3 +++ 1 file changed, 3 insertions(+) --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2128,6 +2128,9 @@ bool __mpol_equal(struct mempolicy *a, s 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();
