The commit is pushed to "branch-rh7-3.10.0-514.16.1.vz7.32.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.16.1.vz7.32.6
------>
commit 74bb8c32e1b5cba31872080c32575cee8b534c7a
Author: Andrey Ryabinin <[email protected]>
Date: Mon Jun 5 16:59:51 2017 +0400
mm/memcg, ub: fix overflow in mem_cgroup_apply_beancounter()
If UBC has unlimited UB_PHYSPAGES/UB_SWAPPAGES
mem_cgroup_apply_beancounter()
will set memcg limits to negative values due to overflow. This will
lead to bogus -ENOMEM.
Add proper check for overflow and also make sure that we don't mem and memsw
bigger than PAGE_COUNTER_MAX as this is maximal possible value for page
counters.
Reported-by: Vladimir Meshkov <[email protected]>
Signed-off-by: Andrey Ryabinin <[email protected]>
---
mm/memcontrol.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fff4cb0..66d51b7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4732,10 +4732,14 @@ int mem_cgroup_apply_beancounter(struct mem_cgroup
*memcg,
mem = ub->ub_parms[UB_PHYSPAGES].limit;
memsw = ub->ub_parms[UB_SWAPPAGES].limit;
- if (memsw < PAGE_COUNTER_MAX - mem)
- memsw += mem;
- else
+
+ if (mem > PAGE_COUNTER_MAX)
+ mem = PAGE_COUNTER_MAX;
+
+ if (memsw + mem < mem || memsw + mem > PAGE_COUNTER_MAX)
memsw = PAGE_COUNTER_MAX;
+ else
+ memsw += mem;
oomguar = ub->ub_parms[UB_OOMGUARPAGES].barrier;
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