kmemleak: add clear command support (30b37101) · Commits · 戴 / test

Documentation/kmemleak.txt

+30 −0

Original line number	Original line	Diff line number	Diff line
	@@ -27,6 +27,13 @@ To trigger an intermediate memory scan:

	# echo scan > /sys/kernel/debug/kmemleak		# echo scan > /sys/kernel/debug/kmemleak

			To clear the list of all current possible memory leaks:

			# echo clear > /sys/kernel/debug/kmemleak

			New leaks will then come up upon reading /sys/kernel/debug/kmemleak
			again.

	Note that the orphan objects are listed in the order they were allocated		Note that the orphan objects are listed in the order they were allocated
	and one object at the beginning of the list may cause other subsequent		and one object at the beginning of the list may cause other subsequent
	objects to be reported as orphan.		objects to be reported as orphan.
	@@ -42,6 +49,8 @@ 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
			clear - clear list of current memory leak suspects, done by
			marking all current reported unreferenced objects grey
	dump=<addr> - dump information about the object found at <addr>		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
	@@ -87,6 +96,27 @@ avoid this, kmemleak can also store the number of values pointing to an
	address inside the block address range that need to be found so that the		address inside the block address range that need to be found so that the
	block is not considered a leak. One example is __vmalloc().		block is not considered a leak. One example is __vmalloc().

			Testing specific sections with kmemleak
			---------------------------------------

			Upon initial bootup your /sys/kernel/debug/kmemleak output page may be
			quite extensive. This can also be the case if you have very buggy code
			when doing development. To work around these situations you can use the
			'clear' command to clear all reported unreferenced objects from the
			/sys/kernel/debug/kmemleak output. By issuing a 'scan' after a 'clear'
			you can find new unreferenced objects; this should help with testing
			specific sections of code.

			To test a critical section on demand with a clean kmemleak do:

			# echo clear > /sys/kernel/debug/kmemleak
			... test your kernel or modules ...
			# echo scan > /sys/kernel/debug/kmemleak

			Then as usual to get your report with:

			# cat /sys/kernel/debug/kmemleak

	Kmemleak API		Kmemleak API
	------------		------------

mm/kmemleak.c

+26 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1420,6 +1420,28 @@ static int dump_str_object_info(const char *str)
	return 0;		return 0;
	}		}

			/*
			* We use grey instead of black to ensure we can do future scans on the same
			* objects. If we did not do future scans these black objects could
			* potentially contain references to newly allocated objects in the future and
			* we'd end up with false positives.
			*/
			static void kmemleak_clear(void)
			{
			struct kmemleak_object *object;
			unsigned long flags;

			rcu_read_lock();
			list_for_each_entry_rcu(object, &object_list, object_list) {
			spin_lock_irqsave(&object->lock, flags);
			if ((object->flags & OBJECT_REPORTED) &&
			unreferenced_object(object))
			object->min_count = 0;
			spin_unlock_irqrestore(&object->lock, flags);
			}
			rcu_read_unlock();
			}

	/*		/*
	* 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:
	@@ -1431,6 +1453,8 @@ static int dump_str_object_info(const char *str)
	* 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
			* clear - mark all current reported unreferenced kmemleak objects as
			* grey to ignore printing them
	* dump=... - dump information about the object found at the given address		* 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,
	@@ -1472,6 +1496,8 @@ 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, "clear", 5) == 0)
			kmemleak_clear();
	else if (strncmp(buf, "dump=", 5) == 0)		else if (strncmp(buf, "dump=", 5) == 0)
	ret = dump_str_object_info(buf + 5);		ret = dump_str_object_info(buf + 5);
	else		else

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