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    slab_common: fix the check for duplicate slab names · 69461747
    Mikulas Patocka 提交于
    The patch 3e374919 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 3e374919.
    Acked-by: NDavid Rientjes <rientjes@google.com>
    Acked-by: NChristoph Lameter <cl@linux.com>
    Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
    Cc: stable@vger.kernel.org	# 3.6+
    Signed-off-by: NPekka Enberg <penberg@kernel.org>
    69461747
slab_common.c 17.0 KB