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Commit 189d84ed authored by Catalin Marinas's avatar Catalin Marinas
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kmemleak: Dump object information on request 



By writing dump=<addr> to the kmemleak file, kmemleak will look up an
object with that address and dump the information it has about it to
syslog. This is useful in debugging memory leaks.

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent af98603d

Documentation/kmemleak.txt

+1 −0
Original line number Original line Diff line number Diff line
@@ -42,6 +42,7 @@ Memory scanning parameters can be modified at run-time by writing to the 
  scan=<secs>	- set the automatic memory scanning period in seconds

  scan=<secs>	- set the automatic memory scanning period in seconds

		  (default 600, 0 to stop the automatic scanning)

		  (default 600, 0 to stop the automatic scanning)

  scan		- trigger a memory scan

  scan		- trigger a memory scan

  dump=<addr>	- dump information about the object found at <addr>





Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on

Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on

the kernel command line.

the kernel command line.

mm/kmemleak.c

+25 −0
Original line number Original line Diff line number Diff line
@@ -331,6 +331,7 @@ static void dump_object_info(struct kmemleak_object *object) 
		  object->comm, object->pid, object->jiffies);

		  object->comm, object->pid, object->jiffies);

	pr_notice("  min_count = %d\n", object->min_count);

	pr_notice("  min_count = %d\n", object->min_count);

	pr_notice("  count = %d\n", object->count);

	pr_notice("  count = %d\n", object->count);

	pr_notice("  flags = 0x%lx\n", object->flags);

	pr_notice("  backtrace:\n");

	pr_notice("  backtrace:\n");

	print_stack_trace(&trace, 4);

	print_stack_trace(&trace, 4);

}

}
@@ -1307,6 +1308,27 @@ static int kmemleak_release(struct inode *inode, struct file *file) 
	return seq_release(inode, file);

	return seq_release(inode, file);

}

}





static int dump_str_object_info(const char *str)

{

	unsigned long flags;

	struct kmemleak_object *object;

	unsigned long addr;



	addr= simple_strtoul(str, NULL, 0);

	object = find_and_get_object(addr, 0);

	if (!object) {

		pr_info("Unknown object at 0x%08lx\n", addr);

		return -EINVAL;

	}



	spin_lock_irqsave(&object->lock, flags);

	dump_object_info(object);

	spin_unlock_irqrestore(&object->lock, flags);



	put_object(object);

	return 0;

}



/*

/*

 * File write operation to configure kmemleak at run-time. The following

 * File write operation to configure kmemleak at run-time. The following

 * commands can be written to the /sys/kernel/debug/kmemleak file:

 * commands can be written to the /sys/kernel/debug/kmemleak file:
@@ -1318,6 +1340,7 @@ static int kmemleak_release(struct inode *inode, struct file *file) 
 *   scan=...	- set the automatic memory scanning period in seconds (0 to

 *   scan=...	- set the automatic memory scanning period in seconds (0 to

 *		  disable it)

 *		  disable it)

 *   scan	- trigger a memory scan

 *   scan	- trigger a memory scan

 *   dump=...	- dump information about the object found at the given address

 */

 */

static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,

static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,

			      size_t size, loff_t *ppos)

			      size_t size, loff_t *ppos)
@@ -1358,6 +1381,8 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, 
		}

		}

	} else if (strncmp(buf, "scan", 4) == 0)

	} else if (strncmp(buf, "scan", 4) == 0)

		kmemleak_scan();

		kmemleak_scan();

	else if (strncmp(buf, "dump=", 5) == 0)

		ret = dump_str_object_info(buf + 5);

	else

	else

		ret = -EINVAL;

		ret = -EINVAL;