diff options
Diffstat (limited to 'kernel/events/core.c')
| -rw-r--r-- | kernel/events/core.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 5b5cb620499e..8cca80094624 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6997,6 +6997,15 @@ static int perf_mmap_rb(struct vm_area_struct *vma, struct perf_event *event, if (data_page_nr(event->rb) != nr_pages) return -EINVAL; + /* + * If this event doesn't have mmap_count, we're attempting to + * create an alias of another event's mmap(); this would mean + * both events will end up scribbling the same user_page; + * which makes no sense. + */ + if (!refcount_read(&event->mmap_count)) + return -EBUSY; + if (refcount_inc_not_zero(&event->rb->mmap_count)) { /* * Success -- managed to mmap() the same buffer @@ -7451,7 +7460,7 @@ static void perf_sample_regs_user(struct perf_regs *regs_user, if (user_mode(regs)) { regs_user->abi = perf_reg_abi(current); regs_user->regs = regs; - } else if (!(current->flags & (PF_KTHREAD | PF_USER_WORKER))) { + } else if (is_user_task(current)) { perf_get_regs_user(regs_user, regs); } else { regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; @@ -8091,7 +8100,7 @@ static u64 perf_virt_to_phys(u64 virt) * Try IRQ-safe get_user_page_fast_only first. * If failed, leave phys_addr as 0. */ - if (!(current->flags & (PF_KTHREAD | PF_USER_WORKER))) { + if (is_user_task(current)) { struct page *p; pagefault_disable(); @@ -8206,7 +8215,7 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) { bool kernel = !event->attr.exclude_callchain_kernel; bool user = !event->attr.exclude_callchain_user && - !(current->flags & (PF_KTHREAD | PF_USER_WORKER)); + is_user_task(current); /* Disallow cross-task user callchains. */ bool crosstask = event->ctx->task && event->ctx->task != current; bool defer_user = IS_ENABLED(CONFIG_UNWIND_USER) && user && |