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, 2 insertions, 2 deletions

diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index d11f579d189a..35b4bbfc78ff 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -404,7 +404,7 @@ static struct task_struct * good_sigevent(sigevent_t * event)
 
         if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
                 (!(rtn = find_task_by_pid(event->sigev_notify_thread_id)) ||
-                 rtn->tgid != current->tgid ||
+                 !same_thread_group(rtn, current) ||
                  (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL))
                 return NULL;
 
@@ -608,7 +608,7 @@ static struct k_itimer * lock_timer(timer_t timer_id, unsigned long *flags)
                 spin_lock(&timr->it_lock);
 
                 if ((timr->it_id != timer_id) || !(timr->it_process) ||
-                                timr->it_process->tgid != current->tgid) {
+                                !same_thread_group(timr->it_process, current)) {
                         spin_unlock(&timr->it_lock);
                         spin_unlock_irqrestore(&idr_lock, *flags);
                         timr = NULL;