diff options
| -rw-r--r-- | include/linux/perf_event.h | 5 | ||||
| -rw-r--r-- | kernel/events/core.c | 34 |
2 files changed, 27 insertions, 12 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 16e38c286d46..e8ad3c590a23 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1055,6 +1055,11 @@ static inline int in_software_context(struct perf_event *event) return event->ctx->pmu->task_ctx_nr == perf_sw_context; } +static inline int is_exclusive_pmu(struct pmu *pmu) +{ + return pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE; +} + extern struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; extern void ___perf_sw_event(u32, u64, struct pt_regs *, u64); diff --git a/kernel/events/core.c b/kernel/events/core.c index 5dd19bedbf64..eea9d52b010c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2553,6 +2553,9 @@ unlock: return ret; } +static bool exclusive_event_installable(struct perf_event *event, + struct perf_event_context *ctx); + /* * Attach a performance event to a context. * @@ -2567,6 +2570,8 @@ 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; @@ -4360,7 +4365,7 @@ 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; /* @@ -4391,7 +4396,7 @@ 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() */ @@ -4411,14 +4416,15 @@ 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) { @@ -10947,11 +10953,6 @@ 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): */ @@ -11039,6 +11040,18 @@ 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); } @@ -11075,9 +11088,6 @@ 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; } |