From: Thomas Garnier <thgarnie@google.com>
To: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
gthelen@google.com, vdavydov.dev@gmail.com, mhocko@kernel.org,
Thomas Garnier <thgarnie@google.com>
Subject: [PATCH v4 1/2] memcg: Prevent memcg caches to be both OFF_SLAB & OBJFREELIST_SLAB
Date: Mon, 7 Nov 2016 14:47:20 -0800 [thread overview]
Message-ID: <1478558841-23005-1-git-send-email-thgarnie@google.com> (raw)
From: Greg Thelen <gthelen@google.com>
While testing OBJFREELIST_SLAB integration with pagealloc, we found a
bug where kmem_cache(sys) would be created with both CFLGS_OFF_SLAB &
CFLGS_OBJFREELIST_SLAB. When it happened, critical allocations needed
for loading drivers or creating new caches will fail.
The original kmem_cache is created early making OFF_SLAB not possible.
When kmem_cache(sys) is created, OFF_SLAB is possible and if pagealloc
is enabled it will try to enable it first under certain conditions.
Given kmem_cache(sys) reuses the original flag, you can have both flags
at the same time.
This fix discards allocator specific flags from memcg before calling
create_cache.
The bug exists since 4.6-rc1 and affects testing debug pagealloc
configurations.
Fixes: b03a017bebc4 ("mm/slab: introduce new slab management type, OBJFREELIST_SLAB")
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Tested-by: Thomas Garnier <thgarnie@google.com>
---
Based on next-20161027
---
mm/slab_common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 71f0b28..329b038 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -533,8 +533,8 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
s = create_cache(cache_name, root_cache->object_size,
root_cache->size, root_cache->align,
- root_cache->flags, root_cache->ctor,
- memcg, root_cache);
+ root_cache->flags & CACHE_CREATE_MASK,
+ root_cache->ctor, memcg, root_cache);
/*
* If we could not create a memcg cache, do not complain, because
* that's not critical at all as we can always proceed with the root
--
2.8.0.rc3.226.g39d4020
next reply other threads:[~2016-11-07 22:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-07 22:47 Thomas Garnier [this message]
2016-11-07 22:47 ` [PATCH v4 2/2] mm: Check kmem_create_cache flags are commons Thomas Garnier
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