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Commit a695cb58 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Prevent deleting instances when they are being read 



Add a ref count to the trace_array structure and prevent removal
of instances that have open descriptors.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 121aaee7

kernel/trace/trace.c

+23 −0
Original line number Diff line number Diff line
@@ -2613,6 +2613,8 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) 
		tracing_iter_reset(iter, cpu);

	}



	tr->ref++;



	mutex_unlock(&trace_types_lock);



	return iter;
@@ -2649,6 +2651,10 @@ static int tracing_release(struct inode *inode, struct file *file) 
	tr = iter->tr;



	mutex_lock(&trace_types_lock);



	WARN_ON(!tr->ref);

	tr->ref--;



	for_each_tracing_cpu(cpu) {

		if (iter->buffer_iter[cpu])

			ring_buffer_read_finish(iter->buffer_iter[cpu]);
@@ -4460,6 +4466,10 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp) 
	if (!info)

		return -ENOMEM;



	mutex_lock(&trace_types_lock);



	tr->ref++;



	info->iter.tr		= tr;

	info->iter.cpu_file	= tc->cpu;

	info->iter.trace	= tr->current_trace;
@@ -4470,6 +4480,8 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp) 


	filp->private_data = info;



	mutex_unlock(&trace_types_lock);



	return nonseekable_open(inode, filp);

}
@@ -4568,10 +4580,17 @@ static int tracing_buffers_release(struct inode *inode, struct file *file) 
	struct ftrace_buffer_info *info = file->private_data;

	struct trace_iterator *iter = &info->iter;



	mutex_lock(&trace_types_lock);



	WARN_ON(!iter->tr->ref);

	iter->tr->ref--;



	if (info->spare)

		ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);

	kfree(info);



	mutex_unlock(&trace_types_lock);



	return 0;

}
@@ -5411,6 +5430,10 @@ static int instance_delete(const char *name) 
	if (!found)

		goto out_unlock;



	ret = -EBUSY;

	if (tr->ref)

		goto out_unlock;



	list_del(&tr->list);



	event_trace_del_tracer(tr);

kernel/trace/trace.h

+1 −0
Original line number Diff line number Diff line
@@ -219,6 +219,7 @@ struct trace_array { 
	struct list_head	systems;

	struct list_head	events;

	struct task_struct	*waiter;

	int			ref;

};



enum {