From: Yisheng Xie Date: Thu, 22 Mar 2018 23:17:02 +0000 (-0700) Subject: mm/mempolicy.c: avoid use uninitialized preferred_node X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6ca473201d709e2d061bf770776b96b9024e58df;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git mm/mempolicy.c: avoid use uninitialized preferred_node [ 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. [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 Reported-by: Alexander Potapenko Tested-by: Alexander Potapenko Reviewed-by: Andrew Morton Cc: Dmitriy Vyukov Cc: Vlastimil Babka Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 2d3077ce50cd..ecbda7f5d494 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2128,6 +2128,9 @@ 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();