diff options
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 580da79e38ee..e126ebf2400c 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -6,6 +6,12 @@ #include <linux/mm.h> #include <linux/slab.h> +#include <linux/sched/autogroup.h> +#include <linux/sched/mm.h> +#include <linux/sched/stat.h> +#include <linux/sched/task.h> +#include <linux/sched/task_stack.h> +#include <linux/sched/cputime.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/capability.h> @@ -45,6 +51,7 @@ #include <linux/task_io_accounting_ops.h> #include <linux/tracehook.h> #include <linux/fs_struct.h> +#include <linux/userfaultfd_k.h> #include <linux/init_task.h> #include <linux/perf_event.h> #include <trace/events/sched.h> @@ -538,7 +545,7 @@ static void exit_mm(void) __set_current_state(TASK_RUNNING); down_read(&mm->mmap_sem); } - atomic_inc(&mm->mm_count); + mmgrab(mm); BUG_ON(mm != current->active_mm); /* more a memory barrier than a real lock */ task_lock(current); @@ -547,6 +554,7 @@ static void exit_mm(void) enter_lazy_tlb(mm, current); task_unlock(current); mm_update_next_owner(mm); + userfaultfd_exit(mm); mmput(mm); if (test_thread_flag(TIF_MEMDIE)) exit_oom_victim(); @@ -607,15 +615,18 @@ static struct task_struct *find_new_reaper(struct task_struct *father, return thread; if (father->signal->has_child_subreaper) { + unsigned int ns_level = task_pid(father)->level; /* * Find the first ->is_child_subreaper ancestor in our pid_ns. - * We start from father to ensure we can not look into another - * namespace, this is safe because all its threads are dead. + * We can't check reaper != child_reaper to ensure we do not + * cross the namespaces, the exiting parent could be injected + * by setns() + fork(). + * We check pid->level, this is slightly more efficient than + * task_active_pid_ns(reaper) != task_active_pid_ns(father). */ - for (reaper = father; - !same_thread_group(reaper, child_reaper); + for (reaper = father->real_parent; + task_pid(reaper)->level == ns_level; reaper = reaper->real_parent) { - /* call_usermodehelper() descendants need this check */ if (reaper == &init_task) break; if (!reaper->signal->is_child_subreaper) |