The patch titled
Subject: pidns: use task_active_pid_ns in do_notify_parent
has been added to the -mm tree. Its filename is
pidns-use-task_active_pid_ns-in-do_notify_parent.patch
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From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Subject: pidns: use task_active_pid_ns in do_notify_parent
Using task_active_pid_ns is more robust because it works even after we
have called exit_namespaces. This change allows us to have parent
processes that are zombies. Normally a zombie parent processes is crazy
and the last thing you would want to have but in the case of not letting
the init process of a pid namespace be reaped until all of it's children
are dead and reaped a zombie parent process is exactly what we want.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Cc: Louis Rilling <louis.rilling@xxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/signal.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff -puN kernel/signal.c~pidns-use-task_active_pid_ns-in-do_notify_parent kernel/signal.c
--- a/kernel/signal.c~pidns-use-task_active_pid_ns-in-do_notify_parent
+++ a/kernel/signal.c
@@ -1666,19 +1666,18 @@ bool do_notify_parent(struct task_struct
info.si_signo = sig;
info.si_errno = 0;
/*
- * we are under tasklist_lock here so our parent is tied to
- * us and cannot exit and release its namespace.
+ * We are under tasklist_lock here so our parent is tied to
+ * us and cannot change.
*
- * the only it can is to switch its nsproxy with sys_unshare,
- * bu uncharing pid namespaces is not allowed, so we'll always
- * see relevant namespace
+ * task_active_pid_ns will always return the same pid namespace
+ * until a task passes through release_task.
*
* write_lock() currently calls preempt_disable() which is the
* same as rcu_read_lock(), but according to Oleg, this is not
* correct to rely on this
*/
rcu_read_lock();
- info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
info.si_uid = map_cred_ns(__task_cred(tsk),
task_cred_xxx(tsk->parent, user_ns));
rcu_read_unlock();
_
Subject: Subject: pidns: use task_active_pid_ns in do_notify_parent
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
linux-next.patch
namespaces-fix-leak-on-fork-failure.patch
connector-userns-replace-netlink-uses-of-cap_raised-with-capable.patch
cred-remove-task_is_dead-from-__task_cred-validation.patch
pidns-use-task_active_pid_ns-in-do_notify_parent.patch
pidns-guarantee-that-the-pidns-init-will-be-the-last-pidns-process-reaped.patch
pidns-make-killed-children-autoreap.patch
syscalls-x86-add-__nr_kcmp-syscall-v8.patch
c-r-procfs-add-arg_start-end-env_start-end-and-exit_code-members-to-proc-pid-stat.patch
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