diff --git a/kernel/events/core.c b/kernel/events/core.c index e0db9b5b9cbc704f07fb862bea786a3ba883f3ab..736fe1f531ba3714bd5dd4ceba86d7a2b72e2dcf 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1337,8 +1337,9 @@ static void put_ctx(struct perf_event_context *ctx) * perf_event_context::mutex * perf_event::child_mutex; * perf_event_context::lock - * perf_event::mmap_mutex * mmap_lock + * perf_event::mmap_mutex + * perf_buffer::aux_mutex * perf_addr_filters_head::lock * * cpu_hotplug_lock @@ -6003,17 +6004,17 @@ static void perf_mmap_close(struct vm_area_struct *vma) int mmap_locked = rb->mmap_locked; unsigned long size = perf_data_size(rb); bool detach_rest = false; + struct perf_buffer_ext *rb_ext = container_of(rb, struct perf_buffer_ext, perf_buffer); if (event->pmu->event_unmapped) event->pmu->event_unmapped(event, vma->vm_mm); /* - * rb->aux_mmap_count will always drop before rb->mmap_count and - * event->mmap_count, so it is ok to use event->mmap_mutex to - * serialize with perf_mmap here. + * The AUX buffer is strictly a sub-buffer, serialize using aux_mutex + * to avoid complications. */ if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && - atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { + atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &rb_ext->aux_mutex)) { /* * Stop all AUX events that are writing to this buffer, * so that we can free its AUX pages and corresponding PMU @@ -6030,7 +6031,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) rb_free_aux(rb); WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); - mutex_unlock(&event->mmap_mutex); + mutex_unlock(&rb_ext->aux_mutex); } if (atomic_dec_and_test(&rb->mmap_count)) @@ -6118,7 +6119,9 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) struct perf_event *event = file->private_data; unsigned long user_locked, user_lock_limit; struct user_struct *user = current_user(); + struct mutex *aux_mutex = NULL; struct perf_buffer *rb = NULL; + struct perf_buffer_ext *rb_ext = NULL; unsigned long locked, lock_limit; unsigned long vma_size; unsigned long nr_pages; @@ -6164,6 +6167,10 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) if (!rb) goto aux_unlock; + rb_ext = container_of(rb, struct perf_buffer_ext, perf_buffer); + aux_mutex = &rb_ext->aux_mutex; + mutex_lock(aux_mutex); + aux_offset = READ_ONCE(rb->user_page->aux_offset); aux_size = READ_ONCE(rb->user_page->aux_size); @@ -6315,6 +6322,8 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) atomic_dec(&rb->mmap_count); } aux_unlock: + if (aux_mutex) + mutex_unlock(aux_mutex); mutex_unlock(&event->mmap_mutex); /* diff --git a/kernel/events/internal.h b/kernel/events/internal.h index aa23ffdaf819fb08fd8f1b69701215a697fd3250..95e32e83c7c8c7b1ab4a42cfaf57330c317d4861 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -58,6 +58,11 @@ struct perf_buffer { void *data_pages[]; }; +struct perf_buffer_ext { + struct mutex aux_mutex; + struct perf_buffer perf_buffer; +}; + extern void rb_free(struct perf_buffer *rb); static inline void rb_free_rcu(struct rcu_head *rcu_head) diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 01351e7e25435dacac27888296dc2f77a2e0887d..11c194e9b8d957784b7a3116312b117abbcea756 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -306,6 +306,7 @@ static void ring_buffer_init(struct perf_buffer *rb, long watermark, int flags) { long max_size = perf_data_size(rb); + struct perf_buffer_ext *rb_ext = container_of(rb, struct perf_buffer_ext, perf_buffer); if (watermark) rb->watermark = min(max_size, watermark); @@ -329,6 +330,8 @@ ring_buffer_init(struct perf_buffer *rb, long watermark, int flags) */ if (!rb->nr_pages) rb->paused = 1; + + mutex_init(&rb_ext->aux_mutex); } void perf_aux_output_flag(struct perf_output_handle *handle, u64 flags) @@ -808,20 +811,22 @@ static void perf_mmap_free_page(void *addr) struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) { + struct perf_buffer_ext *rb_ext; struct perf_buffer *rb; unsigned long size; int i; - size = sizeof(struct perf_buffer); + size = sizeof(struct perf_buffer_ext); size += nr_pages * sizeof(void *); if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER) goto fail; - rb = kzalloc(size, GFP_KERNEL); - if (!rb) + rb_ext = kzalloc(size, GFP_KERNEL); + if (!rb_ext) goto fail; + rb = &rb_ext->perf_buffer; rb->user_page = perf_mmap_alloc_page(cpu); if (!rb->user_page) goto fail_user_page; @@ -845,7 +850,7 @@ struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) perf_mmap_free_page(rb->user_page); fail_user_page: - kfree(rb); + kfree(rb_ext); fail: return NULL; @@ -854,11 +859,12 @@ struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) void rb_free(struct perf_buffer *rb) { int i; + struct perf_buffer_ext *rb_ext = container_of(rb, struct perf_buffer_ext, perf_buffer); perf_mmap_free_page(rb->user_page); for (i = 0; i < rb->nr_pages; i++) perf_mmap_free_page(rb->data_pages[i]); - kfree(rb); + kfree(rb_ext); } #else @@ -881,6 +887,7 @@ static void perf_mmap_unmark_page(void *addr) static void rb_free_work(struct work_struct *work) { + struct perf_buffer_ext *rb_ext; struct perf_buffer *rb; void *base; int i, nr; @@ -894,7 +901,8 @@ static void rb_free_work(struct work_struct *work) perf_mmap_unmark_page(base + (i * PAGE_SIZE)); vfree(base); - kfree(rb); + rb_ext = container_of(rb, struct perf_buffer_ext, perf_buffer); + kfree(rb_ext); } void rb_free(struct perf_buffer *rb) @@ -904,17 +912,19 @@ void rb_free(struct perf_buffer *rb) struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) { + struct perf_buffer_ext *rb_ext; struct perf_buffer *rb; unsigned long size; void *all_buf; - size = sizeof(struct perf_buffer); + size = sizeof(struct perf_buffer_ext); size += sizeof(void *); - rb = kzalloc(size, GFP_KERNEL); - if (!rb) + rb_ext = kzalloc(size, GFP_KERNEL); + if (!rb_ext) goto fail; + rb = &rb_ext->perf_buffer; INIT_WORK(&rb->work, rb_free_work); all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE); @@ -933,7 +943,7 @@ struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags) return rb; fail_all_buf: - kfree(rb); + kfree(rb_ext); fail: return NULL;