kmemleak: Add more cond_resched() calls in the scanning thread
Following recent fix to no longer reschedule in the scan_block()
function, the system may become unresponsive with !PREEMPT. This patch
re-adds the cond_resched() call to scan_block() but conditioned by the
allow_resched parameter.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 6006553..93f1481 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -807,7 +807,7 @@
* found to the gray list.
*/
static void scan_block(void *_start, void *_end,
- struct kmemleak_object *scanned)
+ struct kmemleak_object *scanned, int allow_resched)
{
unsigned long *ptr;
unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
@@ -818,6 +818,8 @@
unsigned long pointer = *ptr;
struct kmemleak_object *object;
+ if (allow_resched)
+ cond_resched();
if (scan_should_stop())
break;
@@ -881,12 +883,12 @@
goto out;
if (hlist_empty(&object->area_list))
scan_block((void *)object->pointer,
- (void *)(object->pointer + object->size), object);
+ (void *)(object->pointer + object->size), object, 0);
else
hlist_for_each_entry(area, elem, &object->area_list, node)
scan_block((void *)(object->pointer + area->offset),
(void *)(object->pointer + area->offset
- + area->length), object);
+ + area->length), object, 0);
out:
spin_unlock_irqrestore(&object->lock, flags);
}
@@ -931,14 +933,14 @@
rcu_read_unlock();
/* data/bss scanning */
- scan_block(_sdata, _edata, NULL);
- scan_block(__bss_start, __bss_stop, NULL);
+ scan_block(_sdata, _edata, NULL, 1);
+ scan_block(__bss_start, __bss_stop, NULL, 1);
#ifdef CONFIG_SMP
/* per-cpu sections scanning */
for_each_possible_cpu(i)
scan_block(__per_cpu_start + per_cpu_offset(i),
- __per_cpu_end + per_cpu_offset(i), NULL);
+ __per_cpu_end + per_cpu_offset(i), NULL, 1);
#endif
/*
@@ -960,7 +962,7 @@
/* only scan if page is in use */
if (page_count(page) == 0)
continue;
- scan_block(page, page + 1, NULL);
+ scan_block(page, page + 1, NULL, 1);
}
}
@@ -972,7 +974,8 @@
read_lock(&tasklist_lock);
for_each_process(task)
scan_block(task_stack_page(task),
- task_stack_page(task) + THREAD_SIZE, NULL);
+ task_stack_page(task) + THREAD_SIZE,
+ NULL, 0);
read_unlock(&tasklist_lock);
}