Merge tag 'sched-urgent-2022-08-06' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-microblaze.git] / mm / kmemleak.c

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index dc1aa9a..1eddc01 100644 (file)
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1474,12 +1474,16 @@ static void kmemleak_scan(void)
        struct zone *zone;
        int __maybe_unused i;
        int new_leaks = 0;
+       int loop1_cnt = 0;
 
        jiffies_last_scan = jiffies;
 
        /* prepare the kmemleak_object's */
        rcu_read_lock();
        list_for_each_entry_rcu(object, &object_list, object_list) {
+               bool obj_pinned = false;
+
+               loop1_cnt++;
                raw_spin_lock_irq(&object->lock);
 #ifdef DEBUG
                /*
@@ -1505,10 +1509,32 @@ static void kmemleak_scan(void)
 
                /* reset the reference count (whiten the object) */
                object->count = 0;
-               if (color_gray(object) && get_object(object))
+               if (color_gray(object) && get_object(object)) {
                        list_add_tail(&object->gray_list, &gray_list);
+                       obj_pinned = true;
+               }
 
                raw_spin_unlock_irq(&object->lock);
+
+               /*
+                * Do a cond_resched() to avoid soft lockup every 64k objects.
+                * Make sure a reference has been taken so that the object
+                * won't go away without RCU read lock.
+                */
+               if (!(loop1_cnt & 0xffff)) {
+                       if (!obj_pinned && !get_object(object)) {
+                               /* Try the next object instead */
+                               loop1_cnt--;
+                               continue;
+                       }
+
+                       rcu_read_unlock();
+                       cond_resched();
+                       rcu_read_lock();
+
+                       if (!obj_pinned)
+                               put_object(object);
+               }
        }
        rcu_read_unlock();
 
@@ -1576,6 +1602,13 @@ static void kmemleak_scan(void)
         */
        rcu_read_lock();
        list_for_each_entry_rcu(object, &object_list, object_list) {
+               /*
+                * This is racy but we can save the overhead of lock/unlock
+                * calls. The missed objects, if any, should be caught in
+                * the next scan.
+                */
+               if (!color_white(object))
+                       continue;
                raw_spin_lock_irq(&object->lock);
                if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
                    && update_checksum(object) && get_object(object)) {
@@ -1603,6 +1636,13 @@ static void kmemleak_scan(void)
         */
        rcu_read_lock();
        list_for_each_entry_rcu(object, &object_list, object_list) {
+               /*
+                * This is racy but we can save the overhead of lock/unlock
+                * calls. The missed objects, if any, should be caught in
+                * the next scan.
+                */
+               if (!color_white(object))
+                       continue;
                raw_spin_lock_irq(&object->lock);
                if (unreferenced_object(object) &&
                    !(object->flags & OBJECT_REPORTED)) {