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>
---
arch/s390/include/asm/debug.h | 3 ++-
arch/s390/kernel/debug.c | 8 ++++----
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/s390/include/asm/debug.h b/arch/s390/include/asm/debug.h
index 0206c80..df7b54e 100644
--- a/arch/s390/include/asm/debug.h
+++ b/arch/s390/include/asm/debug.h
@@ -10,6 +10,7 @@
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/time.h>
+#include <linux/refcount.h>
#include <uapi/asm/debug.h>
#define DEBUG_MAX_LEVEL 6 /* debug levels range from 0 to 6 */
@@ -31,7 +32,7 @@ struct debug_view;
typedef struct debug_info {
struct debug_info* next;
struct debug_info* prev;
- atomic_t ref_count;
+ refcount_t ref_count;
spinlock_t lock;
int level;
int nr_areas;
diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 20a5a42..e4b9929 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -277,7 +277,7 @@ debug_info_alloc(const char *name, int pages_per_area, int nr_areas,
memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
memset(rc->debugfs_entries, 0 ,DEBUG_MAX_VIEWS *
sizeof(struct dentry*));
- atomic_set(&(rc->ref_count), 0);
+ refcount_set(&(rc->ref_count), 0);
return rc;
@@ -361,7 +361,7 @@ debug_info_create(const char *name, int pages_per_area, int nr_areas,
debug_area_last = rc;
rc->next = NULL;
- debug_info_get(rc);
+ refcount_set(&rc->ref_count, 1);
out:
return rc;
}
@@ -416,7 +416,7 @@ static void
debug_info_get(debug_info_t * db_info)
{
if (db_info)
- atomic_inc(&db_info->ref_count);
+ refcount_inc(&db_info->ref_count);
}
/*
@@ -431,7 +431,7 @@ debug_info_put(debug_info_t *db_info)
if (!db_info)
return;
- if (atomic_dec_and_test(&db_info->ref_count)) {
+ if (refcount_dec_and_test(&db_info->ref_count)) {
for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
if (!db_info->views[i])
continue;
--
2.7.4
