perf/core: Fix exclusive events' grouping

[thirdparty/kernel/stable.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f33bd0a8939166a37f7f237e47f9477d36b6c66d..fb875139b8c0ab5fee99237d2712eaae673df60d 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2543,6 +2543,9 @@ unlock:
        return ret;
 }
 
+static bool exclusive_event_installable(struct perf_event *event,
+                                       struct perf_event_context *ctx);
+
 /*
  * Attach a performance event to a context.
  *
@@ -2557,6 +2560,8 @@ perf_install_in_context(struct perf_event_context *ctx,
 
        lockdep_assert_held(&ctx->mutex);
 
+       WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
+
        if (event->cpu != -1)
                event->cpu = cpu;
 
@@ -4348,7 +4353,7 @@ static int exclusive_event_init(struct perf_event *event)
 {
        struct pmu *pmu = event->pmu;
 
-       if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
+       if (!is_exclusive_pmu(pmu))
                return 0;
 
        /*
@@ -4379,7 +4384,7 @@ static void exclusive_event_destroy(struct perf_event *event)
 {
        struct pmu *pmu = event->pmu;
 
-       if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
+       if (!is_exclusive_pmu(pmu))
                return;
 
        /* see comment in exclusive_event_init() */
@@ -4399,14 +4404,15 @@ static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
        return false;
 }
 
-/* Called under the same ctx::mutex as perf_install_in_context() */
 static bool exclusive_event_installable(struct perf_event *event,
                                        struct perf_event_context *ctx)
 {
        struct perf_event *iter_event;
        struct pmu *pmu = event->pmu;
 
-       if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
+       lockdep_assert_held(&ctx->mutex);
+
+       if (!is_exclusive_pmu(pmu))
                return true;
 
        list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
@@ -10899,11 +10905,6 @@ SYSCALL_DEFINE5(perf_event_open,
                goto err_alloc;
        }
 
-       if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
-               err = -EBUSY;
-               goto err_context;
-       }
-
        /*
         * Look up the group leader (we will attach this event to it):
         */
@@ -10991,6 +10992,18 @@ SYSCALL_DEFINE5(perf_event_open,
                                move_group = 0;
                        }
                }
+
+               /*
+                * Failure to create exclusive events returns -EBUSY.
+                */
+               err = -EBUSY;
+               if (!exclusive_event_installable(group_leader, ctx))
+                       goto err_locked;
+
+               for_each_sibling_event(sibling, group_leader) {
+                       if (!exclusive_event_installable(sibling, ctx))
+                               goto err_locked;
+               }
        } else {
                mutex_lock(&ctx->mutex);
        }
@@ -11027,9 +11040,6 @@ SYSCALL_DEFINE5(perf_event_open,
         * because we need to serialize with concurrent event creation.
         */
        if (!exclusive_event_installable(event, ctx)) {
-               /* exclusive and group stuff are assumed mutually exclusive */
-               WARN_ON_ONCE(move_group);
-
                err = -EBUSY;
                goto err_locked;
        }