Revision c7b285550544c22bc005ec20978472c9ac7138c6 authored by Al Viro on 08 March 2012, 17:51:19 UTC, committed by Linus Torvalds on 10 March 2012, 02:59:59 UTC
Current code has put_ioctx() called asynchronously from aio_fput_routine(); that's done *after* we have killed the request that used to pin ioctx, so there's nothing to stop io_destroy() waiting in wait_for_all_aios() from progressing. As the result, we can end up with async call of put_ioctx() being the last one and possibly happening during exit_mmap() or elf_core_dump(), neither of which expects stray munmap() being done to them... We do need to prevent _freeing_ ioctx until aio_fput_routine() is done with that, but that's all we care about - neither io_destroy() nor exit_aio() will progress past wait_for_all_aios() until aio_fput_routine() does really_put_req(), so the ioctx teardown won't be done until then and we don't care about the contents of ioctx past that point. Since actual freeing of these suckers is RCU-delayed, we don't need to bump ioctx refcount when request goes into list for async removal. All we need is rcu_read_lock held just over the ->ctx_lock-protected area in aio_fput_routine(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 86b62a2
pcompress.c
/*
* Cryptographic API.
*
* Partial (de)compression operations.
*
* Copyright 2008 Sony Corporation
*
* 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; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program.
* If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/crypto.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>
#include <crypto/compress.h>
#include <crypto/internal/compress.h>
#include "internal.h"
static int crypto_pcomp_init(struct crypto_tfm *tfm, u32 type, u32 mask)
{
return 0;
}
static unsigned int crypto_pcomp_extsize(struct crypto_alg *alg)
{
return alg->cra_ctxsize;
}
static int crypto_pcomp_init_tfm(struct crypto_tfm *tfm)
{
return 0;
}
#ifdef CONFIG_NET
static int crypto_pcomp_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_comp rpcomp;
snprintf(rpcomp.type, CRYPTO_MAX_ALG_NAME, "%s", "pcomp");
NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
sizeof(struct crypto_report_comp), &rpcomp);
return 0;
nla_put_failure:
return -EMSGSIZE;
}
#else
static int crypto_pcomp_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
static void crypto_pcomp_show(struct seq_file *m, struct crypto_alg *alg)
__attribute__ ((unused));
static void crypto_pcomp_show(struct seq_file *m, struct crypto_alg *alg)
{
seq_printf(m, "type : pcomp\n");
}
static const struct crypto_type crypto_pcomp_type = {
.extsize = crypto_pcomp_extsize,
.init = crypto_pcomp_init,
.init_tfm = crypto_pcomp_init_tfm,
#ifdef CONFIG_PROC_FS
.show = crypto_pcomp_show,
#endif
.report = crypto_pcomp_report,
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_PCOMPRESS,
.tfmsize = offsetof(struct crypto_pcomp, base),
};
struct crypto_pcomp *crypto_alloc_pcomp(const char *alg_name, u32 type,
u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_pcomp_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_pcomp);
int crypto_register_pcomp(struct pcomp_alg *alg)
{
struct crypto_alg *base = &alg->base;
base->cra_type = &crypto_pcomp_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_PCOMPRESS;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_pcomp);
int crypto_unregister_pcomp(struct pcomp_alg *alg)
{
return crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_pcomp);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Partial (de)compression type");
MODULE_AUTHOR("Sony Corporation");
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