diff --git a/kernel/events/core.c b/kernel/events/core.c index b7f4aaedb5fff229917127a9d4bf0fb8faa14765..ff875ddf4aebb69de02325b79429f858828a4885 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6101,6 +6101,10 @@ perf_sample_ustack_size(u16 stack_size, u16 header_size, if (!regs) return 0; + /* No mm, no stack, no dump. */ + if (!current->mm) + return 0; + /* * Check if we fit in with the requested stack size into the: * - TASK_SIZE @@ -6563,6 +6567,9 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) const u32 max_stack = event->attr.sample_max_stack; struct perf_callchain_entry *callchain; + if (!current->mm) + user = false; + if (!kernel && !user) return &__empty_callchain; diff --git a/kernel/exit.c b/kernel/exit.c index 2a32d32bdc03d3d88c04917082f5c2d63f07b816..358a635743ac4a29007f2ab4c50686b5457a431d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -783,6 +783,15 @@ void __noreturn do_exit(long code) tsk->exit_code = code; taskstats_exit(tsk, group_dead); + /* + * Since sampling can touch ->mm, make sure to stop everything before we + * tear it down. + * + * Also flushes inherited counters to the parent - before the parent + * gets woken up by child-exit notifications. + */ + perf_event_exit_task(tsk); + exit_mm(); if (group_dead) @@ -799,14 +808,6 @@ void __noreturn do_exit(long code) exit_task_work(tsk); exit_thread(tsk); - /* - * Flush inherited counters to the parent - before the parent - * gets woken up by child-exit notifications. - * - * because of cgroup mode, must be called before cgroup_exit() - */ - perf_event_exit_task(tsk); - sched_autogroup_exit_task(tsk); cgroup_exit(tsk);