The patch titled
Subject: memcg: fix per_node_info cleanup
has been removed from the -mm tree. Its filename was
memcg-fix-per_node_info-cleanup.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: memcg: fix per_node_info cleanup
syzbot has triggered a NULL ptr dereference when allocation fault
injection enforces a failure and alloc_mem_cgroup_per_node_info
initializes memcg->nodeinfo only half way through. __mem_cgroup_free
still tries to free all per-node data and dereferences pn->lruvec_stat_cpu
unconditioanlly even if the specific per-node data hasn't been
initialized.
The bug is quite unlikely to hit because small allocations do not fail and
we would need quite some numa nodes to make struct mem_cgroup_per_node
large enough to cross the costly order.
Link: http://lkml.kernel.org/r/20180406100906.17790-1-mhocko@xxxxxxxxxx
Reported-by: syzbot+8a5de3cce7cdc70e9ebe@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 00f3ca2c2d66 ("mm: memcontrol: per-lruvec stats infrastructure")
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN mm/memcontrol.c~memcg-fix-per_node_info-cleanup mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-fix-per_node_info-cleanup
+++ a/mm/memcontrol.c
@@ -4108,6 +4108,9 @@ static void free_mem_cgroup_per_node_inf
{
struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
+ if (!pn)
+ return;
+
free_percpu(pn->lruvec_stat_cpu);
kfree(pn);
}
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
mm-oom-docs-describe-the-cgroup-aware-oom-killer-fix-2.patch
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