Add the needed pieces for persistent events which makes them process-agnostic. Also, make their buffers read-only when mmaping them from userspace.
Signed-off-by: Borislav Petkov <[email protected]> --- include/uapi/linux/perf_event.h | 3 ++- kernel/events/core.c | 8 +++++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 9fa9c622a7f4..4a4ae56195e1 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -270,8 +270,9 @@ struct perf_event_attr { exclude_callchain_kernel : 1, /* exclude kernel callchains */ exclude_callchain_user : 1, /* exclude user callchains */ + persistent : 1, /* always-on event */ - __reserved_1 : 41; + __reserved_1 : 40; union { __u32 wakeup_events; /* wakeup every n events */ diff --git a/kernel/events/core.c b/kernel/events/core.c index b0cd86501c30..7c712b0c3b9a 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3560,6 +3560,9 @@ static void perf_mmap_close(struct vm_area_struct *vma) { struct perf_event *event = vma->vm_file->private_data; + if (event->attr.persistent) + return atomic_dec(&event->mmap_count); + if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) { unsigned long size = perf_data_size(event->rb); struct user_struct *user = event->mmap_user; @@ -3603,7 +3606,10 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) if (event->cpu == -1 && event->attr.inherit) return -EINVAL; - if (!(vma->vm_flags & VM_SHARED)) + if (!(vma->vm_flags & VM_SHARED) && !event->attr.persistent) + return -EINVAL; + + if (event->attr.persistent && (vma->vm_flags & VM_WRITE)) return -EINVAL; vma_size = vma->vm_end - vma->vm_start; -- 1.8.1.3.535.ga923c31 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
