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Commit f943fe0f authored by Dmitry Vyukov's avatar Dmitry Vyukov Committed by Ingo Molnar
Browse files

lockdep: Fix report formatting 



Since commit:

  4bcc595c ("printk: reinstate KERN_CONT for printing continuation lines")

printk() requires KERN_CONT to continue log messages. Lots of printk()
in lockdep.c and print_ip_sym() don't have it. As the result lockdep
reports are completely messed up.

Add missing KERN_CONT and inline print_ip_sym() where necessary.

Example of a messed up report:

  0-rc5+ #41 Not tainted
  -------------------------------------------------------
  syz-executor0/5036 is trying to acquire lock:
   (
  rtnl_mutex
  ){+.+.+.}
  , at:
  [<ffffffff86b3d6ac>] rtnl_lock+0x1c/0x20
  but task is already holding lock:
   (
  &net->packet.sklist_lock
  ){+.+...}
  , at:
  [<ffffffff873541a6>] packet_diag_dump+0x1a6/0x1920
  which lock already depends on the new lock.
  the existing dependency chain (in reverse order) is:
  -> #3
   (
  &net->packet.sklist_lock
  +.+...}
  ...

Without this patch all scripts that parse kernel bug reports are broken.

Signed-off-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andreyknvl@google.com
Cc: aryabinin@virtuozzo.com
Cc: joe@perches.com
Cc: syzkaller@googlegroups.com
Link: http://lkml.kernel.org/r/1480343083-48731-1-git-send-email-dvyukov@google.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1be5d4fa

kernel/locking/lockdep.c

+57 −54
Original line number Diff line number Diff line
@@ -506,13 +506,13 @@ static void __print_lock_name(struct lock_class *class) 
	name = class->name;

	if (!name) {

		name = __get_key_name(class->key, str);

		printk("%s", name);

		printk(KERN_CONT "%s", name);

	} else {

		printk("%s", name);

		printk(KERN_CONT "%s", name);

		if (class->name_version > 1)

			printk("#%d", class->name_version);

			printk(KERN_CONT "#%d", class->name_version);

		if (class->subclass)

			printk("/%d", class->subclass);

			printk(KERN_CONT "/%d", class->subclass);

	}

}
@@ -522,9 +522,9 @@ static void print_lock_name(struct lock_class *class) 


	get_usage_chars(class, usage);



	printk(" (");

	printk(KERN_CONT " (");

	__print_lock_name(class);

	printk("){%s}", usage);

	printk(KERN_CONT "){%s}", usage);

}



static void print_lockdep_cache(struct lockdep_map *lock)
@@ -536,7 +536,7 @@ static void print_lockdep_cache(struct lockdep_map *lock) 
	if (!name)

		name = __get_key_name(lock->key->subkeys, str);



	printk("%s", name);

	printk(KERN_CONT "%s", name);

}



static void print_lock(struct held_lock *hlock)
@@ -551,13 +551,13 @@ static void print_lock(struct held_lock *hlock) 
	barrier();



	if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) {

		printk("<RELEASED>\n");

		printk(KERN_CONT "<RELEASED>\n");

		return;

	}



	print_lock_name(lock_classes + class_idx - 1);

	printk(", at: ");

	print_ip_sym(hlock->acquire_ip);

	printk(KERN_CONT ", at: [<%p>] %pS\n",

		(void *)hlock->acquire_ip, (void *)hlock->acquire_ip);

}



static void lockdep_print_held_locks(struct task_struct *curr)
@@ -792,8 +792,8 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) 


		printk("\nnew class %p: %s", class->key, class->name);

		if (class->name_version > 1)

			printk("#%d", class->name_version);

		printk("\n");

			printk(KERN_CONT "#%d", class->name_version);

		printk(KERN_CONT "\n");

		dump_stack();



		if (!graph_lock()) {
@@ -1071,7 +1071,7 @@ print_circular_bug_entry(struct lock_list *target, int depth) 
		return 0;

	printk("\n-> #%u", depth);

	print_lock_name(target->class);

	printk(":\n");

	printk(KERN_CONT ":\n");

	print_stack_trace(&target->trace, 6);



	return 0;
@@ -1102,11 +1102,11 @@ print_circular_lock_scenario(struct held_lock *src, 
	if (parent != source) {

		printk("Chain exists of:\n  ");

		__print_lock_name(source);

		printk(" --> ");

		printk(KERN_CONT " --> ");

		__print_lock_name(parent);

		printk(" --> ");

		printk(KERN_CONT " --> ");

		__print_lock_name(target);

		printk("\n\n");

		printk(KERN_CONT "\n\n");

	}



	printk(" Possible unsafe locking scenario:\n\n");
@@ -1114,16 +1114,16 @@ print_circular_lock_scenario(struct held_lock *src, 
	printk("       ----                    ----\n");

	printk("  lock(");

	__print_lock_name(target);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("                               lock(");

	__print_lock_name(parent);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("                               lock(");

	__print_lock_name(target);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("  lock(");

	__print_lock_name(source);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("\n *** DEADLOCK ***\n\n");

}
@@ -1359,22 +1359,22 @@ static void print_lock_class_header(struct lock_class *class, int depth) 


	printk("%*s->", depth, "");

	print_lock_name(class);

	printk(" ops: %lu", class->ops);

	printk(" {\n");

	printk(KERN_CONT " ops: %lu", class->ops);

	printk(KERN_CONT " {\n");



	for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {

		if (class->usage_mask & (1 << bit)) {

			int len = depth;



			len += printk("%*s   %s", depth, "", usage_str[bit]);

			len += printk(" at:\n");

			len += printk(KERN_CONT " at:\n");

			print_stack_trace(class->usage_traces + bit, len);

		}

	}

	printk("%*s }\n", depth, "");



	printk("%*s ... key      at: ",depth,"");

	print_ip_sym((unsigned long)class->key);

	printk("%*s ... key      at: [<%p>] %pS\n",

		depth, "", class->key, class->key);

}



/*
@@ -1437,11 +1437,11 @@ print_irq_lock_scenario(struct lock_list *safe_entry, 
	if (middle_class != unsafe_class) {

		printk("Chain exists of:\n  ");

		__print_lock_name(safe_class);

		printk(" --> ");

		printk(KERN_CONT " --> ");

		__print_lock_name(middle_class);

		printk(" --> ");

		printk(KERN_CONT " --> ");

		__print_lock_name(unsafe_class);

		printk("\n\n");

		printk(KERN_CONT "\n\n");

	}



	printk(" Possible interrupt unsafe locking scenario:\n\n");
@@ -1449,18 +1449,18 @@ print_irq_lock_scenario(struct lock_list *safe_entry, 
	printk("       ----                    ----\n");

	printk("  lock(");

	__print_lock_name(unsafe_class);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("                               local_irq_disable();\n");

	printk("                               lock(");

	__print_lock_name(safe_class);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("                               lock(");

	__print_lock_name(middle_class);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("  <Interrupt>\n");

	printk("    lock(");

	__print_lock_name(safe_class);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("\n *** DEADLOCK ***\n\n");

}
@@ -1497,9 +1497,9 @@ print_bad_irq_dependency(struct task_struct *curr, 
	print_lock(prev);

	printk("which would create a new lock dependency:\n");

	print_lock_name(hlock_class(prev));

	printk(" ->");

	printk(KERN_CONT " ->");

	print_lock_name(hlock_class(next));

	printk("\n");

	printk(KERN_CONT "\n");



	printk("\nbut this new dependency connects a %s-irq-safe lock:\n",

		irqclass);
@@ -1521,8 +1521,7 @@ print_bad_irq_dependency(struct task_struct *curr, 


	lockdep_print_held_locks(curr);



	printk("\nthe dependencies between %s-irq-safe lock", irqclass);

	printk(" and the holding lock:\n");

	printk("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass);

	if (!save_trace(&prev_root->trace))

		return 0;

	print_shortest_lock_dependencies(backwards_entry, prev_root);
@@ -1694,10 +1693,10 @@ print_deadlock_scenario(struct held_lock *nxt, 
	printk("       ----\n");

	printk("  lock(");

	__print_lock_name(prev);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("  lock(");

	__print_lock_name(next);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("\n *** DEADLOCK ***\n\n");

	printk(" May be due to missing lock nesting notation\n\n");

}
@@ -1891,9 +1890,9 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, 
		graph_unlock();

		printk("\n new dependency: ");

		print_lock_name(hlock_class(prev));

		printk(" => ");

		printk(KERN_CONT " => ");

		print_lock_name(hlock_class(next));

		printk("\n");

		printk(KERN_CONT "\n");

		dump_stack();

		return graph_lock();

	}
@@ -2343,11 +2342,11 @@ print_usage_bug_scenario(struct held_lock *lock) 
	printk("       ----\n");

	printk("  lock(");

	__print_lock_name(class);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("  <Interrupt>\n");

	printk("    lock(");

	__print_lock_name(class);

	printk(");\n");

	printk(KERN_CONT ");\n");

	printk("\n *** DEADLOCK ***\n\n");

}
@@ -2522,14 +2521,18 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this, 
void print_irqtrace_events(struct task_struct *curr)

{

	printk("irq event stamp: %u\n", curr->irq_events);

	printk("hardirqs last  enabled at (%u): ", curr->hardirq_enable_event);

	print_ip_sym(curr->hardirq_enable_ip);

	printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);

	print_ip_sym(curr->hardirq_disable_ip);

	printk("softirqs last  enabled at (%u): ", curr->softirq_enable_event);

	print_ip_sym(curr->softirq_enable_ip);

	printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);

	print_ip_sym(curr->softirq_disable_ip);

	printk("hardirqs last  enabled at (%u): [<%p>] %pS\n",

		curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip,

		(void *)curr->hardirq_enable_ip);

	printk("hardirqs last disabled at (%u): [<%p>] %pS\n",

		curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip,

		(void *)curr->hardirq_disable_ip);

	printk("softirqs last  enabled at (%u): [<%p>] %pS\n",

		curr->softirq_enable_event, (void *)curr->softirq_enable_ip,

		(void *)curr->softirq_enable_ip);

	printk("softirqs last disabled at (%u): [<%p>] %pS\n",

		curr->softirq_disable_event, (void *)curr->softirq_disable_ip,

		(void *)curr->softirq_disable_ip);

}



static int HARDIRQ_verbose(struct lock_class *class)
@@ -3235,8 +3238,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, 
	if (very_verbose(class)) {

		printk("\nacquire class [%p] %s", class->key, class->name);

		if (class->name_version > 1)

			printk("#%d", class->name_version);

		printk("\n");

			printk(KERN_CONT "#%d", class->name_version);

		printk(KERN_CONT "\n");

		dump_stack();

	}
@@ -3378,7 +3381,7 @@ print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, 
	printk("%s/%d is trying to release lock (",

		curr->comm, task_pid_nr(curr));

	print_lockdep_cache(lock);

	printk(") at:\n");

	printk(KERN_CONT ") at:\n");

	print_ip_sym(ip);

	printk("but there are no more locks to release!\n");

	printk("\nother info that might help us debug this:\n");
@@ -3871,7 +3874,7 @@ print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, 
	printk("%s/%d is trying to contend lock (",

		curr->comm, task_pid_nr(curr));

	print_lockdep_cache(lock);

	printk(") at:\n");

	printk(KERN_CONT ") at:\n");

	print_ip_sym(ip);

	printk("but there are no locks held!\n");

	printk("\nother info that might help us debug this:\n");