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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ecb.c
/*
* ECB: Electronic CodeBook mode
*
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.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/algapi.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
struct crypto_ecb_ctx {
struct crypto_cipher *child;
};
static int crypto_ecb_setkey(struct crypto_tfm *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(parent);
struct crypto_cipher *child = ctx->child;
int err;
crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_cipher_setkey(child, key, keylen);
crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int crypto_ecb_crypt(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
struct crypto_cipher *tfm,
void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
{
int bsize = crypto_cipher_blocksize(tfm);
unsigned int nbytes;
int err;
err = blkcipher_walk_virt(desc, walk);
while ((nbytes = walk->nbytes)) {
u8 *wsrc = walk->src.virt.addr;
u8 *wdst = walk->dst.virt.addr;
do {
fn(crypto_cipher_tfm(tfm), wdst, wsrc);
wsrc += bsize;
wdst += bsize;
} while ((nbytes -= bsize) >= bsize);
err = blkcipher_walk_done(desc, walk, nbytes);
}
return err;
}
static int crypto_ecb_encrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct blkcipher_walk walk;
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
blkcipher_walk_init(&walk, dst, src, nbytes);
return crypto_ecb_crypt(desc, &walk, child,
crypto_cipher_alg(child)->cia_encrypt);
}
static int crypto_ecb_decrypt(struct blkcipher_desc *desc,
struct scatterlist *dst, struct scatterlist *src,
unsigned int nbytes)
{
struct blkcipher_walk walk;
struct crypto_blkcipher *tfm = desc->tfm;
struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
blkcipher_walk_init(&walk, dst, src, nbytes);
return crypto_ecb_crypt(desc, &walk, child,
crypto_cipher_alg(child)->cia_decrypt);
}
static int crypto_ecb_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_cipher *cipher;
cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctx->child = cipher;
return 0;
}
static void crypto_ecb_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->child);
}
static struct crypto_instance *crypto_ecb_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_alg *alg;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(alg))
return ERR_CAST(alg);
inst = crypto_alloc_instance("ecb", alg);
if (IS_ERR(inst))
goto out_put_alg;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = alg->cra_blocksize;
inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_type = &crypto_blkcipher_type;
inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
inst->alg.cra_ctxsize = sizeof(struct crypto_ecb_ctx);
inst->alg.cra_init = crypto_ecb_init_tfm;
inst->alg.cra_exit = crypto_ecb_exit_tfm;
inst->alg.cra_blkcipher.setkey = crypto_ecb_setkey;
inst->alg.cra_blkcipher.encrypt = crypto_ecb_encrypt;
inst->alg.cra_blkcipher.decrypt = crypto_ecb_decrypt;
out_put_alg:
crypto_mod_put(alg);
return inst;
}
static void crypto_ecb_free(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}
static struct crypto_template crypto_ecb_tmpl = {
.name = "ecb",
.alloc = crypto_ecb_alloc,
.free = crypto_ecb_free,
.module = THIS_MODULE,
};
static int __init crypto_ecb_module_init(void)
{
return crypto_register_template(&crypto_ecb_tmpl);
}
static void __exit crypto_ecb_module_exit(void)
{
crypto_unregister_template(&crypto_ecb_tmpl);
}
module_init(crypto_ecb_module_init);
module_exit(crypto_ecb_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ECB block cipher algorithm");
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