Alexander reported an 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 use numa_node_id() instead of preferred_node, however, __mpol_equeue() use preferred_node without check whether it is MPOL_F_LOCAL or not. Reported-by: Alexander Potapenko <glider@xxxxxxxxxx> Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> --- mm/mempolicy.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d879f1d..641545e 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(); -- 1.8.3.1
