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>
---
include/linux/ceph/libceph.h | 3 ++-
net/ceph/snapshot.c | 6 +++---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index 1816c5e..26dc674 100644
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -14,6 +14,7 @@
#include <linux/wait.h>
#include <linux/writeback.h>
#include <linux/slab.h>
+#include <linux/refcount.h>
#include <linux/ceph/types.h>
#include <linux/ceph/messenger.h>
@@ -159,7 +160,7 @@ struct ceph_client {
* dirtied.
*/
struct ceph_snap_context {
- atomic_t nref;
+ refcount_t nref;
u64 seq;
u32 num_snaps;
u64 snaps[];
diff --git a/net/ceph/snapshot.c b/net/ceph/snapshot.c
index 705414e..e14a5d0 100644
--- a/net/ceph/snapshot.c
+++ b/net/ceph/snapshot.c
@@ -49,7 +49,7 @@ struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
if (!snapc)
return NULL;
- atomic_set(&snapc->nref, 1);
+ refcount_set(&snapc->nref, 1);
snapc->num_snaps = snap_count;
return snapc;
@@ -59,7 +59,7 @@ EXPORT_SYMBOL(ceph_create_snap_context);
struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc)
{
if (sc)
- atomic_inc(&sc->nref);
+ refcount_inc(&sc->nref);
return sc;
}
EXPORT_SYMBOL(ceph_get_snap_context);
@@ -68,7 +68,7 @@ void ceph_put_snap_context(struct ceph_snap_context *sc)
{
if (!sc)
return;
- if (atomic_dec_and_test(&sc->nref)) {
+ if (refcount_dec_and_test(&sc->nref)) {
/*printk(" deleting snap_context %p\n", sc);*/
kfree(sc);
}
--
2.7.4
--
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