[PATCH] mm/mempolicy: Fix an incorrect rebind node in mpol_rebind_nodemask

From: zhong jiang
Date: Sat May 25 2019 - 03:12:21 EST


We bind an different node to different vma, Unluckily,
it will bind different vma to same node by checking the /proc/pid/numa_maps.
Commit 213980c0f23b ("mm, mempolicy: simplify rebinding mempolicies when updating cpusets")
has introduced the issue. when we change memory policy by seting cpuset.mems,
A process will rebind the specified policy more than one times.
if the cpuset_mems_allowed is not equal to user specified nodes. hence the issue will trigger.
Maybe result in the out of memory which allocating memory from same node.

Fixes: 213980c0f23b ("mm, mempolicy: simplify rebinding mempolicies when updating cpusets")
Signed-off-by: zhong jiang <zhongjiang@xxxxxxxxxx>
---
mm/mempolicy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index e3ab1d9..a60a3be 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -345,7 +345,7 @@ static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
else {
nodes_remap(tmp, pol->v.nodes,pol->w.cpuset_mems_allowed,
*nodes);
- pol->w.cpuset_mems_allowed = tmp;
+ pol->w.cpuset_mems_allowed = *nodes;
}

if (nodes_empty(tmp))
--
1.7.12.4