The patch titled
Subject: mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()
has been added to the -mm tree. Its filename is
mm-slab_common-allow-null-cache-pointer-in-kmem_cache_destroy.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slab_common-allow-null-cache-pointer-in-kmem_cache_destroy.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab_common-allow-null-cache-pointer-in-kmem_cache_destroy.patch
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------------------------------------------------------
From: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Subject: mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()
kmem_cache_destroy() does not tolerate a NULL kmem_cache pointer argument
and performs a NULL-pointer dereference. This requires additional
attention and effort from developers/reviewers and forces all
kmem_cache_destroy() callers (200+ as of 4.1) to do a NULL check
if (cache)
kmem_cache_destroy(cache);
Or, otherwise, be invalid kmem_cache_destroy() users.
Tweak kmem_cache_destroy() and NULL-check the pointer there.
Proposed by Andrew Morton.
Link: https://lkml.org/lkml/2015/6/8/583
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Julia Lawall <julia.lawall@xxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab_common.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN mm/slab_common.c~mm-slab_common-allow-null-cache-pointer-in-kmem_cache_destroy mm/slab_common.c
--- a/mm/slab_common.c~mm-slab_common-allow-null-cache-pointer-in-kmem_cache_destroy
+++ a/mm/slab_common.c
@@ -641,6 +641,9 @@ void kmem_cache_destroy(struct kmem_cach
bool need_rcu_barrier = false;
bool busy = false;
+ if (unlikely(!s))
+ return;
+
BUG_ON(!is_root_cache(s));
get_online_cpus();
_
Patches currently in -mm which might be from sergey.senozhatsky@xxxxxxxxx are
mm-slab_common-allow-null-cache-pointer-in-kmem_cache_destroy.patch
mm-mempool-allow-null-pool-pointer-in-mempool_destroy.patch
mm-dmapool-allow-null-pool-pointer-in-dma_pool_destroy.patch
mm-zpool-allow-null-zpool-pointer-in-zpool_destroy_pool.patch
mm-zsmalloc-allow-null-pool-pointer-in-zs_destroy_pool.patch
zsmalloc-drop-unused-variable-nr_to_migrate.patch
zsmalloc-always-keep-per-class-stats.patch
zsmalloc-introduce-zs_can_compact-function.patch
zsmalloc-cosmetic-compaction-code-adjustments.patch
zsmalloc-zram-introduce-zs_pool_stats-api.patch
zsmalloc-account-the-number-of-compacted-pages.patch
zsmalloc-use-shrinker-to-trigger-auto-compaction.patch
zsmalloc-partial-page-ordering-within-a-fullness_list.patch
zsmalloc-consider-zs_almost_full-as-migrate-source.patch
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