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_bmap_item.c | 4 ++--
fs/xfs/xfs_bmap_item.h | 4 +++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 9bf57c7..33104ad 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -199,7 +199,7 @@ xfs_bui_init(
buip->bui_format.bui_nextents = XFS_BUI_MAX_FAST_EXTENTS;
buip->bui_format.bui_id = (uintptr_t)(void *)buip;
atomic_set(&buip->bui_next_extent, 0);
- atomic_set(&buip->bui_refcount, 2);
+ refcount_set(&buip->bui_refcount, 2);
return buip;
}
@@ -215,7 +215,7 @@ void
xfs_bui_release(
struct xfs_bui_log_item *buip)
{
- if (atomic_dec_and_test(&buip->bui_refcount)) {
+ if (refcount_dec_and_test(&buip->bui_refcount)) {
xfs_trans_ail_remove(&buip->bui_item, SHUTDOWN_LOG_IO_ERROR);
xfs_bui_item_free(buip);
}
diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
index c867daa..988a6ae 100644
--- a/fs/xfs/xfs_bmap_item.h
+++ b/fs/xfs/xfs_bmap_item.h
@@ -20,6 +20,8 @@
#ifndef __XFS_BMAP_ITEM_H__
#define __XFS_BMAP_ITEM_H__
+#include <linux/refcount.h>
+
/*
* There are (currently) two pairs of bmap btree redo item types: map & unmap.
* The common abbreviations for these are BUI (bmap update intent) and BUD
@@ -61,7 +63,7 @@ struct kmem_zone;
*/
struct xfs_bui_log_item {
struct xfs_log_item bui_item;
- atomic_t bui_refcount;
+ refcount_t bui_refcount;
atomic_t bui_next_extent;
unsigned long bui_flags; /* misc flags */
struct xfs_bui_log_format bui_format;
--
2.7.4
--
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