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perf counters: group counter, fixes

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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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2008-12-11 11:26:29 +01:00
parent 04289bb989
commit ccff286d85
1 changed files with 20 additions and 19 deletions
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39
kernel/perf_counter.c
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@ -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 */
@ -876,32 +870,39 @@ 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;
/*
* Do not allow to attach to a group in a different
* task or CPU context:
*/
if (group_leader->ctx != ctx)
goto err_put_context;
}
/*
* Get the target context (task or percpu):
*/
ctx = find_get_context(pid, cpu);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
ret = -ENOMEM;
counter = perf_counter_alloc(&hw_event, cpu, group_leader);
if (!counter)