Revision 50338b889dc504c69e0cb316ac92d1b9e51f3c8a authored by Török Edwin on 15 June 2011, 21:06:14 UTC, committed by Al Viro on 16 June 2011, 15:27:39 UTC
Git bisection shows that commit e6bc45d65df8599fdbae73be9cec4ceed274db53 causes BUG_ONs under high I/O load: kernel BUG at fs/inode.c:1368! [ 2862.501007] Call Trace: [ 2862.501007] [<ffffffff811691d8>] d_kill+0xf8/0x140 [ 2862.501007] [<ffffffff81169c19>] dput+0xc9/0x190 [ 2862.501007] [<ffffffff8115577f>] fput+0x15f/0x210 [ 2862.501007] [<ffffffff81152171>] filp_close+0x61/0x90 [ 2862.501007] [<ffffffff81152251>] sys_close+0xb1/0x110 [ 2862.501007] [<ffffffff814c14fb>] system_call_fastpath+0x16/0x1b A reliable way to reproduce this bug is: Login to KDE, run 'rsnapshot sync', and apt-get install openjdk-6-jdk, and apt-get remove openjdk-6-jdk. The buggy part of the patch is this: struct inode *inode = NULL; ..... - if (nd.last.name[nd.last.len]) - goto slashes; inode = dentry->d_inode; - if (inode) - ihold(inode); + if (nd.last.name[nd.last.len] || !inode) + goto slashes; + ihold(inode) ... if (inode) iput(inode); /* truncate the inode here */ If nd.last.name[nd.last.len] is nonzero (and thus goto slashes branch is taken), and dentry->d_inode is non-NULL, then this code now does an additional iput on the inode, which is wrong. Fix this by only setting the inode variable if nd.last.name[nd.last.len] is 0. Reference: https://lkml.org/lkml/2011/6/15/50 Reported-by: Norbert Preining <preining@logic.at> Reported-by: Török Edwin <edwintorok@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Török Edwin <edwintorok@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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crypto_null.c
/*
* Cryptographic API.
*
* Null algorithms, aka Much Ado About Nothing.
*
* These are needed for IPsec, and may be useful in general for
* testing & debugging.
*
* The null cipher is compliant with RFC2410.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/string.h>
#define NULL_KEY_SIZE 0
#define NULL_BLOCK_SIZE 1
#define NULL_DIGEST_SIZE 0
#define NULL_IV_SIZE 0
static int null_compress(struct crypto_tfm *tfm, const u8 *src,
unsigned int slen, u8 *dst, unsigned int *dlen)
{
if (slen > *dlen)
return -EINVAL;
memcpy(dst, src, slen);
*dlen = slen;
return 0;
}
static int null_init(struct shash_desc *desc)
{
return 0;
}
static int null_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
return 0;
}
static int null_final(struct shash_desc *desc, u8 *out)
{
return 0;
}
static int null_digest(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *out)
{
return 0;
}
static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
unsigned int keylen)
{ return 0; }
static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{ return 0; }
static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
memcpy(dst, src, NULL_BLOCK_SIZE);
}
static int skcipher_null_crypt(struct blkcipher_desc *desc,
struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes)
{
struct blkcipher_walk walk;
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt(desc, &walk);
while (walk.nbytes) {
if (walk.src.virt.addr != walk.dst.virt.addr)
memcpy(walk.dst.virt.addr, walk.src.virt.addr,
walk.nbytes);
err = blkcipher_walk_done(desc, &walk, 0);
}
return err;
}
static struct crypto_alg compress_null = {
.cra_name = "compress_null",
.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
.cra_blocksize = NULL_BLOCK_SIZE,
.cra_ctxsize = 0,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(compress_null.cra_list),
.cra_u = { .compress = {
.coa_compress = null_compress,
.coa_decompress = null_compress } }
};
static struct shash_alg digest_null = {
.digestsize = NULL_DIGEST_SIZE,
.setkey = null_hash_setkey,
.init = null_init,
.update = null_update,
.finup = null_digest,
.digest = null_digest,
.final = null_final,
.base = {
.cra_name = "digest_null",
.cra_flags = CRYPTO_ALG_TYPE_SHASH,
.cra_blocksize = NULL_BLOCK_SIZE,
.cra_module = THIS_MODULE,
}
};
static struct crypto_alg cipher_null = {
.cra_name = "cipher_null",
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = NULL_BLOCK_SIZE,
.cra_ctxsize = 0,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(cipher_null.cra_list),
.cra_u = { .cipher = {
.cia_min_keysize = NULL_KEY_SIZE,
.cia_max_keysize = NULL_KEY_SIZE,
.cia_setkey = null_setkey,
.cia_encrypt = null_crypt,
.cia_decrypt = null_crypt } }
};
static struct crypto_alg skcipher_null = {
.cra_name = "ecb(cipher_null)",
.cra_driver_name = "ecb-cipher_null",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
.cra_blocksize = NULL_BLOCK_SIZE,
.cra_type = &crypto_blkcipher_type,
.cra_ctxsize = 0,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(skcipher_null.cra_list),
.cra_u = { .blkcipher = {
.min_keysize = NULL_KEY_SIZE,
.max_keysize = NULL_KEY_SIZE,
.ivsize = NULL_IV_SIZE,
.setkey = null_setkey,
.encrypt = skcipher_null_crypt,
.decrypt = skcipher_null_crypt } }
};
MODULE_ALIAS("compress_null");
MODULE_ALIAS("digest_null");
MODULE_ALIAS("cipher_null");
static int __init crypto_null_mod_init(void)
{
int ret = 0;
ret = crypto_register_alg(&cipher_null);
if (ret < 0)
goto out;
ret = crypto_register_alg(&skcipher_null);
if (ret < 0)
goto out_unregister_cipher;
ret = crypto_register_shash(&digest_null);
if (ret < 0)
goto out_unregister_skcipher;
ret = crypto_register_alg(&compress_null);
if (ret < 0)
goto out_unregister_digest;
out:
return ret;
out_unregister_digest:
crypto_unregister_shash(&digest_null);
out_unregister_skcipher:
crypto_unregister_alg(&skcipher_null);
out_unregister_cipher:
crypto_unregister_alg(&cipher_null);
goto out;
}
static void __exit crypto_null_mod_fini(void)
{
crypto_unregister_alg(&compress_null);
crypto_unregister_shash(&digest_null);
crypto_unregister_alg(&skcipher_null);
crypto_unregister_alg(&cipher_null);
}
module_init(crypto_null_mod_init);
module_exit(crypto_null_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Null Cryptographic Algorithms");
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