Commit d4c5a2f5 authored by Ingo Molnar's avatar Ingo Molnar Committed by Thomas Gleixner
Browse files

ftrace: fix locking 



we can hold all cpu trace buffer locks at once - put each into a
separate lock class.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent b3806b43

kernel/trace/trace.c

+3 −5
Original line number Diff line number Diff line
@@ -1865,11 +1865,8 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, 


	}



	for_each_possible_cpu(cpu) {

	for_each_cpu_mask(cpu, mask) {

		data = iter->tr->data[cpu];



		if (!cpu_isset(cpu, mask))

			continue;

		spin_unlock(&data->lock);

		atomic_dec(&data->disabled);

	}
@@ -2076,6 +2073,7 @@ static int trace_alloc_page(void) 
	for_each_possible_cpu(i) {

		data = global_trace.data[i];

		spin_lock_init(&data->lock);

		lockdep_set_class(&data->lock, &data->lock_key);

		page = list_entry(pages.next, struct page, lru);

		list_del_init(&page->lru);

		list_add_tail(&page->lru, &data->trace_pages);
@@ -2084,6 +2082,7 @@ static int trace_alloc_page(void) 
#ifdef CONFIG_TRACER_MAX_TRACE

		data = max_tr.data[i];

		spin_lock_init(&data->lock);

		lockdep_set_class(&data->lock, &data->lock_key);

		page = list_entry(pages.next, struct page, lru);

		list_del_init(&page->lru);

		list_add_tail(&page->lru, &data->trace_pages);
@@ -2203,5 +2202,4 @@ __init static int tracer_alloc_buffers(void) 
	}

	return ret;

}



fs_initcall(tracer_alloc_buffers);

kernel/trace/trace.h

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ struct trace_array_cpu { 
	struct list_head	trace_pages;

	atomic_t		disabled;

	spinlock_t		lock;

	struct lock_class_key	lock_key;

	cycle_t			time_offset;



	/* these fields get copied into max-trace: */