Revision f3f99d63a8156c7a4a6b20aac22b53c5579c7dc1 authored by Hugh Dickins on 21 August 2020, 00:42:02 UTC, committed by Linus Torvalds on 21 August 2020, 16:52:53 UTC
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in __khugepaged_enter(): yes, when one thread is about to dump core, has set core_state, and is waiting for others, another might do something calling __khugepaged_enter(), which now crashes because I lumped the core_state test (known as "mmget_still_valid") into khugepaged_test_exit(). I still think it's best to lump them together, so just in this exceptional case, check mm->mm_users directly instead of khugepaged_test_exit(). Fixes: bbe98f9cadff ("khugepaged: khugepaged_test_exit() check mmget_still_valid()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Yang Shi <shy828301@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Song Liu <songliubraving@fb.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Eric Dumazet <edumazet@google.com> Cc: <stable@vger.kernel.org> [4.8+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent d5a1695
des_generic.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Cryptographic API.
*
* DES & Triple DES EDE Cipher Algorithms.
*
* Copyright (c) 2005 Dag Arne Osvik <da@osvik.no>
*/
#include <asm/byteorder.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/crypto.h>
#include <crypto/internal/des.h>
static int des_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
struct des_ctx *dctx = crypto_tfm_ctx(tfm);
int err;
err = des_expand_key(dctx, key, keylen);
if (err == -ENOKEY) {
if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)
err = -EINVAL;
else
err = 0;
}
if (err)
memset(dctx, 0, sizeof(*dctx));
return err;
}
static void crypto_des_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
const struct des_ctx *dctx = crypto_tfm_ctx(tfm);
des_encrypt(dctx, dst, src);
}
static void crypto_des_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
const struct des_ctx *dctx = crypto_tfm_ctx(tfm);
des_decrypt(dctx, dst, src);
}
static int des3_ede_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
struct des3_ede_ctx *dctx = crypto_tfm_ctx(tfm);
int err;
err = des3_ede_expand_key(dctx, key, keylen);
if (err == -ENOKEY) {
if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)
err = -EINVAL;
else
err = 0;
}
if (err)
memset(dctx, 0, sizeof(*dctx));
return err;
}
static void crypto_des3_ede_encrypt(struct crypto_tfm *tfm, u8 *dst,
const u8 *src)
{
const struct des3_ede_ctx *dctx = crypto_tfm_ctx(tfm);
des3_ede_encrypt(dctx, dst, src);
}
static void crypto_des3_ede_decrypt(struct crypto_tfm *tfm, u8 *dst,
const u8 *src)
{
const struct des3_ede_ctx *dctx = crypto_tfm_ctx(tfm);
des3_ede_decrypt(dctx, dst, src);
}
static struct crypto_alg des_algs[2] = { {
.cra_name = "des",
.cra_driver_name = "des-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = DES_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct des_ctx),
.cra_module = THIS_MODULE,
.cra_u = { .cipher = {
.cia_min_keysize = DES_KEY_SIZE,
.cia_max_keysize = DES_KEY_SIZE,
.cia_setkey = des_setkey,
.cia_encrypt = crypto_des_encrypt,
.cia_decrypt = crypto_des_decrypt } }
}, {
.cra_name = "des3_ede",
.cra_driver_name = "des3_ede-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = DES3_EDE_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct des3_ede_ctx),
.cra_module = THIS_MODULE,
.cra_u = { .cipher = {
.cia_min_keysize = DES3_EDE_KEY_SIZE,
.cia_max_keysize = DES3_EDE_KEY_SIZE,
.cia_setkey = des3_ede_setkey,
.cia_encrypt = crypto_des3_ede_encrypt,
.cia_decrypt = crypto_des3_ede_decrypt } }
} };
static int __init des_generic_mod_init(void)
{
return crypto_register_algs(des_algs, ARRAY_SIZE(des_algs));
}
static void __exit des_generic_mod_fini(void)
{
crypto_unregister_algs(des_algs, ARRAY_SIZE(des_algs));
}
subsys_initcall(des_generic_mod_init);
module_exit(des_generic_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("DES & Triple DES EDE Cipher Algorithms");
MODULE_AUTHOR("Dag Arne Osvik <da@osvik.no>");
MODULE_ALIAS_CRYPTO("des");
MODULE_ALIAS_CRYPTO("des-generic");
MODULE_ALIAS_CRYPTO("des3_ede");
MODULE_ALIAS_CRYPTO("des3_ede-generic");
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