Revision d38a2b7a9c939e6d7329ab92b96559ccebf7b135 authored by Muchun Song on 24 July 2020, 04:15:27 UTC, committed by Linus Torvalds on 24 July 2020, 19:42:41 UTC
If the kmem_cache refcount is greater than one, we should not mark the root kmem_cache as dying. If we mark the root kmem_cache dying incorrectly, the non-root kmem_cache can never be destroyed. It resulted in memory leak when memcg was destroyed. We can use the following steps to reproduce. 1) Use kmem_cache_create() to create a new kmem_cache named A. 2) Coincidentally, the kmem_cache A is an alias for kmem_cache B, so the refcount of B is just increased. 3) Use kmem_cache_destroy() to destroy the kmem_cache A, just decrease the B's refcount but mark the B as dying. 4) Create a new memory cgroup and alloc memory from the kmem_cache B. It leads to create a non-root kmem_cache for allocating memory. 5) When destroy the memory cgroup created in the step 4), the non-root kmem_cache can never be destroyed. If we repeat steps 4) and 5), this will cause a lot of memory leak. So only when refcount reach zero, we mark the root kmem_cache as dying. Fixes: 92ee383f6daa ("mm: fix race between kmem_cache destroy, create and deactivate") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Roman Gushchin <guro@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200716165103.83462-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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aegis.h
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* AEGIS common definitions
*
* Copyright (c) 2018 Ondrej Mosnacek <omosnacek@gmail.com>
* Copyright (c) 2018 Red Hat, Inc. All rights reserved.
*/
#ifndef _CRYPTO_AEGIS_H
#define _CRYPTO_AEGIS_H
#include <crypto/aes.h>
#include <linux/bitops.h>
#include <linux/types.h>
#define AEGIS_BLOCK_SIZE 16
union aegis_block {
__le64 words64[AEGIS_BLOCK_SIZE / sizeof(__le64)];
__le32 words32[AEGIS_BLOCK_SIZE / sizeof(__le32)];
u8 bytes[AEGIS_BLOCK_SIZE];
};
#define AEGIS_BLOCK_ALIGN (__alignof__(union aegis_block))
#define AEGIS_ALIGNED(p) IS_ALIGNED((uintptr_t)p, AEGIS_BLOCK_ALIGN)
static __always_inline void crypto_aegis_block_xor(union aegis_block *dst,
const union aegis_block *src)
{
dst->words64[0] ^= src->words64[0];
dst->words64[1] ^= src->words64[1];
}
static __always_inline void crypto_aegis_block_and(union aegis_block *dst,
const union aegis_block *src)
{
dst->words64[0] &= src->words64[0];
dst->words64[1] &= src->words64[1];
}
static __always_inline void crypto_aegis_aesenc(union aegis_block *dst,
const union aegis_block *src,
const union aegis_block *key)
{
const u8 *s = src->bytes;
const u32 *t = crypto_ft_tab[0];
u32 d0, d1, d2, d3;
d0 = t[s[ 0]] ^ rol32(t[s[ 5]], 8) ^ rol32(t[s[10]], 16) ^ rol32(t[s[15]], 24);
d1 = t[s[ 4]] ^ rol32(t[s[ 9]], 8) ^ rol32(t[s[14]], 16) ^ rol32(t[s[ 3]], 24);
d2 = t[s[ 8]] ^ rol32(t[s[13]], 8) ^ rol32(t[s[ 2]], 16) ^ rol32(t[s[ 7]], 24);
d3 = t[s[12]] ^ rol32(t[s[ 1]], 8) ^ rol32(t[s[ 6]], 16) ^ rol32(t[s[11]], 24);
dst->words32[0] = cpu_to_le32(d0) ^ key->words32[0];
dst->words32[1] = cpu_to_le32(d1) ^ key->words32[1];
dst->words32[2] = cpu_to_le32(d2) ^ key->words32[2];
dst->words32[3] = cpu_to_le32(d3) ^ key->words32[3];
}
#endif /* _CRYPTO_AEGIS_H */
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