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Commit 179a8100 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

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: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reported-by: default avatarEric Paris <eparis@redhat.com>
parent 43ed5d6e

mm/kmemleak.c

+5 −17
Original line number Diff line number Diff line
@@ -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 @@ static const struct file_operations kmemleak_fops = { 
 * 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 @@ static int kmemleak_cleanup_thread(void *arg) 
		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 @@ static void kmemleak_disable(void) 


	/* 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 @@ static int __init kmemleak_late_init(void) 
		 * 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;

	}