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-rw-r--r--mm/kmemleak.c61
1 files changed, 42 insertions, 19 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 37af2dc8dac9..646e2979641f 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1461,6 +1461,27 @@ static void scan_gray_list(void)
}
/*
+ * Conditionally call resched() in a object iteration loop while making sure
+ * that the given object won't go away without RCU read lock by performing a
+ * get_object() if !pinned.
+ *
+ * Return: false if can't do a cond_resched() due to get_object() failure
+ * true otherwise
+ */
+static bool kmemleak_cond_resched(struct kmemleak_object *object, bool pinned)
+{
+ if (!pinned && !get_object(object))
+ return false;
+
+ rcu_read_unlock();
+ cond_resched();
+ rcu_read_lock();
+ if (!pinned)
+ put_object(object);
+ return true;
+}
+
+/*
* Scan data sections and all the referenced memory blocks allocated via the
* kernel's standard allocators. This function must be called with the
* scan_mutex held.
@@ -1471,7 +1492,7 @@ static void kmemleak_scan(void)
struct zone *zone;
int __maybe_unused i;
int new_leaks = 0;
- int loop1_cnt = 0;
+ int loop_cnt = 0;
jiffies_last_scan = jiffies;
@@ -1480,7 +1501,6 @@ static void kmemleak_scan(void)
list_for_each_entry_rcu(object, &object_list, object_list) {
bool obj_pinned = false;
- loop1_cnt++;
raw_spin_lock_irq(&object->lock);
#ifdef DEBUG
/*
@@ -1514,24 +1534,11 @@ static void kmemleak_scan(void)
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.
+ * Do a cond_resched() every 64k objects to avoid soft lockup.
*/
- 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);
- }
+ if (!(++loop_cnt & 0xffff) &&
+ !kmemleak_cond_resched(object, obj_pinned))
+ loop_cnt--; /* Try again on next object */
}
rcu_read_unlock();
@@ -1598,8 +1605,16 @@ static void kmemleak_scan(void)
* scan and color them gray until the next scan.
*/
rcu_read_lock();
+ loop_cnt = 0;
list_for_each_entry_rcu(object, &object_list, object_list) {
/*
+ * Do a cond_resched() every 64k objects to avoid soft lockup.
+ */
+ if (!(++loop_cnt & 0xffff) &&
+ !kmemleak_cond_resched(object, false))
+ loop_cnt--; /* Try again on next object */
+
+ /*
* 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.
@@ -1632,8 +1647,16 @@ static void kmemleak_scan(void)
* Scanning result reporting.
*/
rcu_read_lock();
+ loop_cnt = 0;
list_for_each_entry_rcu(object, &object_list, object_list) {
/*
+ * Do a cond_resched() every 64k objects to avoid soft lockup.
+ */
+ if (!(++loop_cnt & 0xffff) &&
+ !kmemleak_cond_resched(object, false))
+ loop_cnt--; /* Try again on next object */
+
+ /*
* 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.