refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: David Windsor <dwindsor@xxxxxxxxx>
---
fs/xfs/xfs_log.c | 10 +++++-----
fs/xfs/xfs_log_priv.h | 4 +++-
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index b1469f0..c127fa0 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -3500,8 +3500,8 @@ void
xfs_log_ticket_put(
xlog_ticket_t *ticket)
{
- ASSERT(atomic_read(&ticket->t_ref) > 0);
- if (atomic_dec_and_test(&ticket->t_ref))
+ ASSERT(refcount_read(&ticket->t_ref) > 0);
+ if (refcount_dec_and_test(&ticket->t_ref))
kmem_zone_free(xfs_log_ticket_zone, ticket);
}
@@ -3509,8 +3509,8 @@ xlog_ticket_t *
xfs_log_ticket_get(
xlog_ticket_t *ticket)
{
- ASSERT(atomic_read(&ticket->t_ref) > 0);
- atomic_inc(&ticket->t_ref);
+ ASSERT(refcount_read(&ticket->t_ref) > 0);
+ refcount_inc(&ticket->t_ref);
return ticket;
}
@@ -3632,7 +3632,7 @@ xlog_ticket_alloc(
unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
- atomic_set(&tic->t_ref, 1);
+ refcount_set(&tic->t_ref, 1);
tic->t_task = current;
INIT_LIST_HEAD(&tic->t_queue);
tic->t_unit_res = unit_res;
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index c2604a5..279afce 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -18,6 +18,8 @@
#ifndef __XFS_LOG_PRIV_H__
#define __XFS_LOG_PRIV_H__
+#include <linux/refcount.h>
+
struct xfs_buf;
struct xlog;
struct xlog_ticket;
@@ -168,7 +170,7 @@ typedef struct xlog_ticket {
struct list_head t_queue; /* reserve/write queue */
struct task_struct *t_task; /* task that owns this ticket */
xlog_tid_t t_tid; /* transaction identifier : 4 */
- atomic_t t_ref; /* ticket reference count : 4 */
+ refcount_t t_ref; /* ticket reference count : 4 */
int t_curr_res; /* current reservation in bytes : 4 */
int t_unit_res; /* unit reservation in bytes : 4 */
char t_ocnt; /* original count : 1 */
--
2.7.4
--
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