kmemleak: Do no create the clean-up thread during kmemleak_disable()
The kmemleak_disable() function could be called from various contexts
including IRQ. It creates a clean-up thread but the kthread_create()
function has restrictions on which contexts it can be called from,
mainly because of the kthread_create_lock. The patch changes the
kmemleak clean-up thread to a workqueue.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Eric Paris <eparis@redhat.com>
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 74d4089..1563de4 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -92,6 +92,7 @@
#include <linux/string.h>
#include <linux/nodemask.h>
#include <linux/mm.h>
+#include <linux/workqueue.h>
#include <asm/sections.h>
#include <asm/processor.h>
@@ -1499,7 +1500,7 @@
* Perform the freeing of the kmemleak internal objects after waiting for any
* current memory scan to complete.
*/
-static int kmemleak_cleanup_thread(void *arg)
+static void kmemleak_do_cleanup(struct work_struct *work)
{
struct kmemleak_object *object;
@@ -1511,22 +1512,9 @@
delete_object_full(object->pointer);
rcu_read_unlock();
mutex_unlock(&scan_mutex);
-
- return 0;
}
-/*
- * Start the clean-up thread.
- */
-static void kmemleak_cleanup(void)
-{
- struct task_struct *cleanup_thread;
-
- cleanup_thread = kthread_run(kmemleak_cleanup_thread, NULL,
- "kmemleak-clean");
- if (IS_ERR(cleanup_thread))
- pr_warning("Failed to create the clean-up thread\n");
-}
+static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
/*
* Disable kmemleak. No memory allocation/freeing will be traced once this
@@ -1544,7 +1532,7 @@
/* check whether it is too early for a kernel thread */
if (atomic_read(&kmemleak_initialized))
- kmemleak_cleanup();
+ schedule_work(&cleanup_work);
pr_info("Kernel memory leak detector disabled\n");
}
@@ -1640,7 +1628,7 @@
* after setting kmemleak_initialized and we may end up with
* two clean-up threads but serialized by scan_mutex.
*/
- kmemleak_cleanup();
+ schedule_work(&cleanup_work);
return -ENOMEM;
}