lib/ref_tracker: add unlocked leak print helper

To have reliable detection of leaks, caller must be able to check under
the same lock both: tracked counter and the leaks. dir.lock is natural
candidate for such lock and unlocked print helper can be called with this
lock taken.
As a bonus we can reuse this helper in ref_tracker_dir_exit.

Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/ref_tracker.h b/include/linux/ref_tracker.h
index 9ca353ab712b5e897d9b3e5cfcd7117b610dd01a..87a92f2bec1b88beefc902545ee68dcfa12eea5f 100644 (file)
--- a/include/linux/ref_tracker.h
+++ b/include/linux/ref_tracker.h
@@ -36,6 +36,9 @@ static inline void ref_tracker_dir_init(struct ref_tracker_dir *dir,
 
 void ref_tracker_dir_exit(struct ref_tracker_dir *dir);
 
+void ref_tracker_dir_print_locked(struct ref_tracker_dir *dir,
+                                 unsigned int display_limit);
+
 void ref_tracker_dir_print(struct ref_tracker_dir *dir,
                           unsigned int display_limit);
 
@@ -56,6 +59,11 @@ static inline void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
 {
 }
 
+static inline void ref_tracker_dir_print_locked(struct ref_tracker_dir *dir,
+                                               unsigned int display_limit)
+{
+}
+
 static inline void ref_tracker_dir_print(struct ref_tracker_dir *dir,
                                         unsigned int display_limit)
 {

diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
index dc7b14aa3431e2bf7a97a7e78220f04da144563d..d4eb0929af8f96cfd32cb77e1ee3856fb869f891 100644 (file)
--- a/lib/ref_tracker.c
+++ b/lib/ref_tracker.c
@@ -14,6 +14,38 @@ struct ref_tracker {
        depot_stack_handle_t    free_stack_handle;
 };
 
+void ref_tracker_dir_print_locked(struct ref_tracker_dir *dir,
+                                 unsigned int display_limit)
+{
+       struct ref_tracker *tracker;
+       unsigned int i = 0;
+
+       lockdep_assert_held(&dir->lock);
+
+       list_for_each_entry(tracker, &dir->list, head) {
+               if (i < display_limit) {
+                       pr_err("leaked reference.\n");
+                       if (tracker->alloc_stack_handle)
+                               stack_depot_print(tracker->alloc_stack_handle);
+                       i++;
+               } else {
+                       break;
+               }
+       }
+}
+EXPORT_SYMBOL(ref_tracker_dir_print_locked);
+
+void ref_tracker_dir_print(struct ref_tracker_dir *dir,
+                          unsigned int display_limit)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&dir->lock, flags);
+       ref_tracker_dir_print_locked(dir, display_limit);
+       spin_unlock_irqrestore(&dir->lock, flags);
+}
+EXPORT_SYMBOL(ref_tracker_dir_print);
+
 void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
 {
        struct ref_tracker *tracker, *n;
@@ -27,13 +59,13 @@ void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
                kfree(tracker);
                dir->quarantine_avail++;
        }
-       list_for_each_entry_safe(tracker, n, &dir->list, head) {
-               pr_err("leaked reference.\n");
-               if (tracker->alloc_stack_handle)
-                       stack_depot_print(tracker->alloc_stack_handle);
+       if (!list_empty(&dir->list)) {
+               ref_tracker_dir_print_locked(dir, 16);
                leak = true;
-               list_del(&tracker->head);
-               kfree(tracker);
+               list_for_each_entry_safe(tracker, n, &dir->list, head) {
+                       list_del(&tracker->head);
+                       kfree(tracker);
+               }
        }
        spin_unlock_irqrestore(&dir->lock, flags);
        WARN_ON_ONCE(leak);
@@ -42,28 +74,6 @@ void ref_tracker_dir_exit(struct ref_tracker_dir *dir)
 }
 EXPORT_SYMBOL(ref_tracker_dir_exit);
 
-void ref_tracker_dir_print(struct ref_tracker_dir *dir,
-                          unsigned int display_limit)
-{
-       struct ref_tracker *tracker;
-       unsigned long flags;
-       unsigned int i = 0;
-
-       spin_lock_irqsave(&dir->lock, flags);
-       list_for_each_entry(tracker, &dir->list, head) {
-               if (i < display_limit) {
-                       pr_err("leaked reference.\n");
-                       if (tracker->alloc_stack_handle)
-                               stack_depot_print(tracker->alloc_stack_handle);
-                       i++;
-               } else {
-                       break;
-               }
-       }
-       spin_unlock_irqrestore(&dir->lock, flags);
-}
-EXPORT_SYMBOL(ref_tracker_dir_print);
-
 int ref_tracker_alloc(struct ref_tracker_dir *dir,
                      struct ref_tracker **trackerp,
                      gfp_t gfp)