__kernel_fsid_t fsid = {};
fsnotify_foreach_obj_type(type) {
+ struct fsnotify_mark_connector *conn;
+
if (!fsnotify_iter_should_report_type(iter_info, type))
continue;
- fsid = iter_info->marks[type]->connector->fsid;
+ conn = READ_ONCE(iter_info->marks[type]->connector);
+ /* Mark is just getting destroyed or created? */
+ if (!conn)
+ continue;
+ fsid = conn->fsid;
if (WARN_ON_ONCE(!fsid.val[0] && !fsid.val[1]))
continue;
return fsid;
return 0;
}
- if (FAN_GROUP_FLAG(group, FAN_REPORT_FID))
+ if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
fsid = fanotify_get_fsid(iter_info);
+ /* Racing with mark destruction or creation? */
+ if (!fsid.val[0] && !fsid.val[1])
+ return 0;
+ }
event = fanotify_alloc_event(group, inode, mask, data, data_type,
&fsid);
void fsnotify_put_mark(struct fsnotify_mark *mark)
{
- struct fsnotify_mark_connector *conn;
+ struct fsnotify_mark_connector *conn = READ_ONCE(mark->connector);
void *objp = NULL;
unsigned int type = FSNOTIFY_OBJ_TYPE_DETACHED;
bool free_conn = false;
/* Catch marks that were actually never attached to object */
- if (!mark->connector) {
+ if (!conn) {
if (refcount_dec_and_test(&mark->refcnt))
fsnotify_final_mark_destroy(mark);
return;
* We have to be careful so that traversals of obj_list under lock can
* safely grab mark reference.
*/
- if (!refcount_dec_and_lock(&mark->refcnt, &mark->connector->lock))
+ if (!refcount_dec_and_lock(&mark->refcnt, &conn->lock))
return;
- conn = mark->connector;
hlist_del_init_rcu(&mark->obj_list);
if (hlist_empty(&conn->list)) {
objp = fsnotify_detach_connector_from_object(conn, &type);
} else {
__fsnotify_recalc_mask(conn);
}
- mark->connector = NULL;
+ WRITE_ONCE(mark->connector, NULL);
spin_unlock(&conn->lock);
fsnotify_drop_object(type, objp);
/* mark should be the last entry. last is the current last entry */
hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);
added:
- mark->connector = conn;
+ WRITE_ONCE(mark->connector, conn);
out_err:
spin_unlock(&conn->lock);
spin_unlock(&mark->lock);
refcount_set(&mark->refcnt, 1);
fsnotify_get_group(group);
mark->group = group;
+ WRITE_ONCE(mark->connector, NULL);
}
/*