diff options
| -rw-r--r-- | kernel/events/core.c | 20 | ||||
| -rw-r--r-- | kernel/events/ring_buffer.c | 9 |
2 files changed, 17 insertions, 12 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index a7adc8e34089..33210aff3ee6 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7029,7 +7029,6 @@ static void perf_mmap_close(struct vm_area_struct *vma) mapped_f unmapped = get_mapped(event, event_unmapped); struct perf_buffer *rb = ring_buffer_get(event); struct user_struct *mmap_user = rb->mmap_user; - bool detach_rest = false; /* FIXIES vs perf_pmu_unregister() */ if (unmapped) @@ -7060,17 +7059,18 @@ static void perf_mmap_close(struct vm_area_struct *vma) mutex_unlock(&rb->aux_mutex); } - if (refcount_dec_and_test(&rb->mmap_count)) - detach_rest = true; - - if (!refcount_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) - goto out_put; - - ring_buffer_attach(event, NULL); - mutex_unlock(&event->mmap_mutex); + /* + * Drop references in reverse order of perf_mmap() to prevent + * rb revival after rb->mmap_count reaches zero. + */ + if (refcount_dec_and_mutex_lock(&event->mmap_count, + &event->mmap_mutex)) { + ring_buffer_attach(event, NULL); + mutex_unlock(&event->mmap_mutex); + } /* If there's still other mmap()s of this buffer, we're done. */ - if (!detach_rest) + if (!refcount_dec_and_test(&rb->mmap_count)) goto out_put; /* diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 9fe92161715e..1b1ffe0533e5 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -509,7 +509,10 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) /* * Only send RECORD_AUX if we have something useful to communicate * - * Note: the OVERWRITE records by themselves are not considered + * PMU_FORMAT bits identify the PMU type rather than an AUX event + * has occurred, so ignore them for zero-sized records. + * + * The OVERWRITE records by themselves are not considered * useful, as they don't communicate any *new* information, * aside from the short-lived offset, that becomes history at * the next event sched-in and therefore isn't useful. @@ -518,7 +521,9 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size) * offset. So, from now on we don't output AUX records that * have *only* OVERWRITE flag set. */ - if (size || (handle->aux_flags & ~(u64)PERF_AUX_FLAG_OVERWRITE)) + if (size || + (handle->aux_flags & ~(u64)(PERF_AUX_FLAG_PMU_FORMAT_TYPE_MASK | + PERF_AUX_FLAG_OVERWRITE))) perf_event_aux_event(handle->event, aux_head, size, handle->aux_flags); |