From ccff286d85098ba5438e22aa2ea807fc1e18cf2f Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 11 Dec 2008 11:26:29 +0100 Subject: [PATCH] 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: Ingo Molnar --- kernel/perf_counter.c | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index fa59fe8c02d5..278209c547a8 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -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 != group_leader) + goto err_put_context; + /* + * Do not allow to attach to a group in a different + * task or CPU context: */ - if (group_leader->group_leader) - goto out_fput; + 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) -- GitLab