diff options
authorKirill Tkhai <ktkhai@virtuozzo.com>2018-10-05 15:52:10 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-05 16:32:05 -0700
commitb8e57efa2c98cc56c49461c4950cf026422c29e9 (patch)
parent58bc4c34d249bf1bc50730a9a209139347cfacfe (diff)
mm/vmscan.c: fix int overflow in callers of do_shrink_slab()
do_shrink_slab() returns unsigned long value, and the placing into int variable cuts high bytes off. Then we compare ret and 0xfffffffe (since SHRINK_EMPTY is converted to ret type). Thus a large number of objects returned by do_shrink_slab() may be interpreted as SHRINK_EMPTY, if low bytes of their value are equal to 0xfffffffe. Fix that by declaration ret as unsigned long in these functions. Link: http://lkml.kernel.org/r/153813407177.17544.14888305435570723973.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reported-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 4 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c7ce2c161225..c5ef7240cbcb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -580,8 +580,8 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
struct mem_cgroup *memcg, int priority)
struct memcg_shrinker_map *map;
- unsigned long freed = 0;
- int ret, i;
+ unsigned long ret, freed = 0;
+ int i;
if (!memcg_kmem_enabled() || !mem_cgroup_online(memcg))
return 0;
@@ -677,9 +677,8 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
struct mem_cgroup *memcg,
int priority)
+ unsigned long ret, freed = 0;
struct shrinker *shrinker;
- unsigned long freed = 0;
- int ret;
if (!mem_cgroup_is_root(memcg))
return shrink_slab_memcg(gfp_mask, nid, memcg, priority);