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-rw-r--r--kernel/exit.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 580da79e38ee..90b09ca35c84 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -45,6 +45,7 @@
#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>
@@ -547,6 +548,7 @@ 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 +609,18 @@ 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)
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