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_extfree_item.c | 4 ++--
fs/xfs/xfs_extfree_item.h | 4 +++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index d7bc149..4e0acf0 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -220,7 +220,7 @@ xfs_efi_init(
efip->efi_format.efi_nextents = nextents;
efip->efi_format.efi_id = (uintptr_t)(void *)efip;
atomic_set(&efip->efi_next_extent, 0);
- atomic_set(&efip->efi_refcount, 2);
+ refcount_set(&efip->efi_refcount, 2);
return efip;
}
@@ -290,7 +290,7 @@ void
xfs_efi_release(
struct xfs_efi_log_item *efip)
{
- if (atomic_dec_and_test(&efip->efi_refcount)) {
+ if (refcount_dec_and_test(&efip->efi_refcount)) {
xfs_trans_ail_remove(&efip->efi_item, SHUTDOWN_LOG_IO_ERROR);
xfs_efi_item_free(efip);
}
diff --git a/fs/xfs/xfs_extfree_item.h b/fs/xfs/xfs_extfree_item.h
index a32c794..e6da63d 100644
--- a/fs/xfs/xfs_extfree_item.h
+++ b/fs/xfs/xfs_extfree_item.h
@@ -18,6 +18,8 @@
#ifndef __XFS_EXTFREE_ITEM_H__
#define __XFS_EXTFREE_ITEM_H__
+#include <linux/refcount.h>
+
/* kernel only EFI/EFD definitions */
struct xfs_mount;
@@ -64,7 +66,7 @@ struct kmem_zone;
*/
typedef struct xfs_efi_log_item {
xfs_log_item_t efi_item;
- atomic_t efi_refcount;
+ refcount_t efi_refcount;
atomic_t efi_next_extent;
unsigned long efi_flags; /* misc flags */
xfs_efi_log_format_t efi_format;
--
2.7.4
--
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