From: Shakeel Butt <shakeelb@xxxxxxxxxx>
Subject: mm, slab: memcg_link the SLAB's kmem_cache
All the root caches are linked into slab_root_caches which was introduced
by the commit 510ded33e075 ("slab: implement slab_root_caches list") but
it missed to add the SLAB's kmem_cache.
While experimenting with opt-in/opt-out kmem accounting, I noticed system
crashes due to NULL dereference inside cache_from_memcg_idx() while
deferencing kmem_cache.memcg_params.memcg_caches. The upstream clean
kernel will not see these crashes but SLAB should be consistent with SLUB
which does linked its boot caches (kmem_cache_node and kmem_cache) into
slab_root_caches.
Link: http://lkml.kernel.org/r/20180319210020.60289-1-shakeelb@xxxxxxxxxx
Fixes: 510ded33e075c ("slab: implement slab_root_caches list")
Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 1 +
1 file changed, 1 insertion(+)
diff -puN mm/slab.c~mm-slab-memcg_link-the-slabs-kmem_cache mm/slab.c
--- a/mm/slab.c~mm-slab-memcg_link-the-slabs-kmem_cache
+++ a/mm/slab.c
@@ -1283,6 +1283,7 @@ void __init kmem_cache_init(void)
nr_node_ids * sizeof(struct kmem_cache_node *),
SLAB_HWCACHE_ALIGN, 0, 0);
list_add(&kmem_cache->list, &slab_caches);
+ memcg_link_cache(kmem_cache);
slab_state = PARTIAL;
/*
_
--
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