Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 36/46] slub: do not merge cache if slub_debug contains a never-merge flag | Date | Thu, 19 Oct 2017 15:49:12 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Grygorii Maistrenko <grygoriimkd@gmail.com>
[ Upstream commit c6e28895a4372992961888ffaadc9efc643b5bfe ]
In case CONFIG_SLUB_DEBUG_ON=n, find_mergeable() gets debug features from commandline but never checks if there are features from the SLAB_NEVER_MERGE set.
As a result selected by slub_debug caches are always mergeable if they have been created without a custom constructor set or without one of the SLAB_* debug features on.
This moves the SLAB_NEVER_MERGE check below the flags update from commandline to make sure it won't merge the slab cache if one of the debug features is on.
Link: http://lkml.kernel.org/r/20170101124451.GA4740@lp-laptop-d Signed-off-by: Grygorii Maistrenko <grygoriimkd@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- mm/slab_common.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -250,7 +250,7 @@ struct kmem_cache *find_mergeable(size_t { struct kmem_cache *s; - if (slab_nomerge || (flags & SLAB_NEVER_MERGE)) + if (slab_nomerge) return NULL; if (ctor) @@ -261,6 +261,9 @@ struct kmem_cache *find_mergeable(size_t size = ALIGN(size, align); flags = kmem_cache_flags(size, flags, name, NULL); + if (flags & SLAB_NEVER_MERGE) + return NULL; + list_for_each_entry_reverse(s, &slab_caches, list) { if (slab_unmergeable(s)) continue;
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