Isolate some explicit usage of task->tgid

With pid namespaces this field is now dangerous to use explicitly, so hide
it behind the helpers.

Also the pid and pgrp fields o task_struct and signal_struct are to be
deprecated.  Unfortunately this patch cannot be sent right now as this
leads to tons of warnings, so start isolating them, and deprecate later.

Actually the p->tgid == pid has to be changed to has_group_leader_pid(),
but Oleg pointed out that in case of posix cpu timers this is the same, and
thread_group_leader() is more preferable.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index b0ace60ce596..7c76f2ffaeaa 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -169,7 +169,7 @@ int ptrace_attach(struct task_struct *task)
         retval = -EPERM;
         if (task->pid <= 1)
                 goto out;
-        if (task->tgid == current->tgid)
+        if (same_thread_group(task, current))
                 goto out;
 
 repeat: