Commit ccff286d authored by Ingo Molnar's avatar Ingo Molnar
Browse files

perf counters: group counter, fixes 



Impact: bugfix

Check that a group does not span outside the context of a CPU or a task.

Also, do not allow deep recursive hierarchies.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 04289bb9

kernel/perf_counter.c

+20 −19
Original line number Diff line number Diff line
@@ -107,9 +107,6 @@ list_del_counter(struct perf_counter *counter, struct perf_counter_context *ctx) 


	list_del_init(&counter->list_entry);



	if (list_empty(&counter->sibling_list))

		return;



	/*

	 * If this was a group counter with sibling counters then

	 * upgrade the siblings to singleton counters by adding them
@@ -395,9 +392,6 @@ counter_sched_in(struct perf_counter *counter, 
		 struct perf_counter_context *ctx,

		 int cpu)

{

	if (!counter->active)

		return;



	hw_perf_counter_enable(counter);

	counter->active = 1;

	counter->oncpu = cpu;	/* TODO: put 'cpu' into cpuctx->cpu */
@@ -876,31 +870,38 @@ asmlinkage int sys_perf_counter_open( 
		return -EFAULT;



	/*

	 * Look up the group leader:

	 * Get the target context (task or percpu):

	 */

	ctx = find_get_context(pid, cpu);

	if (IS_ERR(ctx))

		return PTR_ERR(ctx);



	/*

	 * Look up the group leader (we will attach this counter to it):

	 */

	group_leader = NULL;

	if (group_fd != -1) {

		ret = -EINVAL;

		group_file = fget_light(group_fd, &fput_needed);

		if (!group_file)

			goto out_fput;

			goto err_put_context;

		if (group_file->f_op != &perf_fops)

			goto out_fput;

			goto err_put_context;



		group_leader = group_file->private_data;

		/*

		 * Do not allow a recursive hierarchy:

		 * Do not allow a recursive hierarchy (this new sibling

		 * becoming part of another group-sibling):

		 */

		if (group_leader->group_leader)

			goto out_fput;

	}



		if (group_leader->group_leader != group_leader)

			goto err_put_context;

		/*

	 * Get the target context (task or percpu):

		 * Do not allow to attach to a group in a different

		 * task or CPU context:

		 */

	ctx = find_get_context(pid, cpu);

	if (IS_ERR(ctx))

		return PTR_ERR(ctx);

		if (group_leader->ctx != ctx)

			goto err_put_context;

	}



	ret = -ENOMEM;

	counter = perf_counter_alloc(&hw_event, cpu, group_leader);