perf: Tighten (and fix) the grouping condition

[cascardo/linux.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 882f835..19efcf1 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6776,7 +6776,6 @@ skip_type:
                __perf_event_init_context(&cpuctx->ctx);
                lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
                lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
-               cpuctx->ctx.type = cpu_context;
                cpuctx->ctx.pmu = pmu;
 
                __perf_cpu_hrtimer_init(cpuctx, cpu);
@@ -7420,7 +7419,19 @@ SYSCALL_DEFINE5(perf_event_open,
                 * task or CPU context:
                 */
                if (move_group) {
-                       if (group_leader->ctx->type != ctx->type)
+                       /*
+                        * Make sure we're both on the same task, or both
+                        * per-cpu events.
+                        */
+                       if (group_leader->ctx->task != ctx->task)
+                               goto err_context;
+
+                       /*
+                        * Make sure we're both events for the same CPU;
+                        * grouping events for different CPUs is broken; since
+                        * you can never concurrently schedule them anyhow.
+                        */
+                       if (group_leader->cpu != event->cpu)
                                goto err_context;
                } else {
                        if (group_leader->ctx != ctx)