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-rw-r--r--include/linux/bpf.h5
-rw-r--r--kernel/bpf/inode.c6
-rw-r--r--kernel/bpf/syscall.c36
-rw-r--r--kernel/bpf/verifier.c3
4 files changed, 33 insertions, 17 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index de464e6683b6..83d1926c61e4 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -40,6 +40,7 @@ struct bpf_map {
struct user_struct *user;
const struct bpf_map_ops *ops;
struct work_struct work;
+ atomic_t usercnt;
};
struct bpf_map_type_list {
@@ -167,8 +168,10 @@ struct bpf_prog *bpf_prog_get(u32 ufd);
void bpf_prog_put(struct bpf_prog *prog);
void bpf_prog_put_rcu(struct bpf_prog *prog);
-struct bpf_map *bpf_map_get(u32 ufd);
+struct bpf_map *bpf_map_get_with_uref(u32 ufd);
struct bpf_map *__bpf_map_get(struct fd f);
+void bpf_map_inc(struct bpf_map *map, bool uref);
+void bpf_map_put_with_uref(struct bpf_map *map);
void bpf_map_put(struct bpf_map *map);
extern int sysctl_unprivileged_bpf_disabled;
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index be6d726e31c9..5a8a797d50b7 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -34,7 +34,7 @@ static void *bpf_any_get(void *raw, enum bpf_type type)
atomic_inc(&((struct bpf_prog *)raw)->aux->refcnt);
break;
case BPF_TYPE_MAP:
- atomic_inc(&((struct bpf_map *)raw)->refcnt);
+ bpf_map_inc(raw, true);
break;
default:
WARN_ON_ONCE(1);
@@ -51,7 +51,7 @@ static void bpf_any_put(void *raw, enum bpf_type type)
bpf_prog_put(raw);
break;
case BPF_TYPE_MAP:
- bpf_map_put(raw);
+ bpf_map_put_with_uref(raw);
break;
default:
WARN_ON_ONCE(1);
@@ -64,7 +64,7 @@ static void *bpf_fd_probe_obj(u32 ufd, enum bpf_type *type)
void *raw;
*type = BPF_TYPE_MAP;
- raw = bpf_map_get(ufd);
+ raw = bpf_map_get_with_uref(ufd);
if (IS_ERR(raw)) {
*type = BPF_TYPE_PROG;
raw = bpf_prog_get(ufd);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0d3313d02a7e..4a8f3c1d7da6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -82,6 +82,14 @@ static void bpf_map_free_deferred(struct work_struct *work)
map->ops->map_free(map);
}
+static void bpf_map_put_uref(struct bpf_map *map)
+{
+ if (atomic_dec_and_test(&map->usercnt)) {
+ if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY)
+ bpf_fd_array_map_clear(map);
+ }
+}
+
/* decrement map refcnt and schedule it for freeing via workqueue
* (unrelying map implementation ops->map_free() might sleep)
*/
@@ -93,17 +101,15 @@ void bpf_map_put(struct bpf_map *map)
}
}
-static int bpf_map_release(struct inode *inode, struct file *filp)
+void bpf_map_put_with_uref(struct bpf_map *map)
{
- struct bpf_map *map = filp->private_data;
-
- if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY)
- /* prog_array stores refcnt-ed bpf_prog pointers
- * release them all when user space closes prog_array_fd
- */
- bpf_fd_array_map_clear(map);
-
+ bpf_map_put_uref(map);
bpf_map_put(map);
+}
+
+static int bpf_map_release(struct inode *inode, struct file *filp)
+{
+ bpf_map_put_with_uref(filp->private_data);
return 0;
}
@@ -142,6 +148,7 @@ static int map_create(union bpf_attr *attr)
return PTR_ERR(map);
atomic_set(&map->refcnt, 1);
+ atomic_set(&map->usercnt, 1);
err = bpf_map_charge_memlock(map);
if (err)
@@ -174,7 +181,14 @@ struct bpf_map *__bpf_map_get(struct fd f)
return f.file->private_data;
}
-struct bpf_map *bpf_map_get(u32 ufd)
+void bpf_map_inc(struct bpf_map *map, bool uref)
+{
+ atomic_inc(&map->refcnt);
+ if (uref)
+ atomic_inc(&map->usercnt);
+}
+
+struct bpf_map *bpf_map_get_with_uref(u32 ufd)
{
struct fd f = fdget(ufd);
struct bpf_map *map;
@@ -183,7 +197,7 @@ struct bpf_map *bpf_map_get(u32 ufd)
if (IS_ERR(map))
return map;
- atomic_inc(&map->refcnt);
+ bpf_map_inc(map, true);
fdput(f);
return map;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c6073056badf..a7945d10b378 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2021,8 +2021,7 @@ static int replace_map_fd_with_map_ptr(struct verifier_env *env)
* will be used by the valid program until it's unloaded
* and all maps are released in free_bpf_prog_info()
*/
- atomic_inc(&map->refcnt);
-
+ bpf_map_inc(map, false);
fdput(f);
next_insn:
insn++;