From: Mikulas Patocka Date: Tue, 4 Mar 2014 22:13:47 +0000 (-0500) Subject: slab_common: fix the check for duplicate slab names X-Git-Tag: upstream/snapshot3+hdmi~1967 X-Git-Url: http://review.tizen.org/git/?p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git;a=commitdiff_plain;h=98f43b46dc4b5d095db3c333556199bfe0041141 slab_common: fix the check for duplicate slab names commit 694617474e33b8603fc76e090ed7d09376514b1a upstream. The patch 3e374919b314f20e2a04f641ebc1093d758f66a4 is supposed to fix the problem where kmem_cache_create incorrectly reports duplicate cache name and fails. The problem is described in the header of that patch. However, the patch doesn't really fix the problem because of these reasons: * the logic to test for debugging is reversed. It was intended to perform the check only if slub debugging is enabled (which implies that caches with the same parameters are not merged). Therefore, there should be #if !defined(CONFIG_SLUB) || defined(CONFIG_SLUB_DEBUG_ON) The current code has the condition reversed and performs the test if debugging is disabled. * slub debugging may be enabled or disabled based on kernel command line, CONFIG_SLUB_DEBUG_ON is just the default settings. Therefore the test based on definition of CONFIG_SLUB_DEBUG_ON is unreliable. This patch fixes the problem by removing the test "!defined(CONFIG_SLUB_DEBUG_ON)". Therefore, duplicate names are never checked if the SLUB allocator is used. Note to stable kernel maintainers: when backporint this patch, please backport also the patch 3e374919b314f20e2a04f641ebc1093d758f66a4. Acked-by: David Rientjes Acked-by: Christoph Lameter Signed-off-by: Mikulas Patocka Signed-off-by: Pekka Enberg Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/slab_common.c b/mm/slab_common.c index 1ec3c61..f149e67 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -56,7 +56,7 @@ static int kmem_cache_sanity_check(struct mem_cgroup *memcg, const char *name, continue; } -#if !defined(CONFIG_SLUB) || !defined(CONFIG_SLUB_DEBUG_ON) +#if !defined(CONFIG_SLUB) /* * For simplicity, we won't check this in the list of memcg * caches. We have control over memcg naming, and if there