ITIMER_REAL: convert to use struct pid

signal_struct->tsk points to the ->group_leader and thus we have the nasty
code in de_thread() which has to change it and restart ->real_timer if the
leader is changed.

Use "struct pid *leader_pid" instead.  This also allows us to kill now
unneeded send_group_sig_info().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 20 deletions

diff --git a/fs/exec.c b/fs/exec.c
index be923e4bc389..927a7c5ef4af 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -782,26 +782,8 @@ static int de_thread(struct task_struct *tsk)
         zap_other_threads(tsk);
         read_unlock(&tasklist_lock);
 
-        /*
-         * Account for the thread group leader hanging around:
-         */
-        count = 1;
-        if (!thread_group_leader(tsk)) {
-                count = 2;
-                /*
-                 * The SIGALRM timer survives the exec, but needs to point
-                 * at us as the new group leader now.  We have a race with
-                 * a timer firing now getting the old leader, so we need to
-                 * synchronize with any firing (by calling del_timer_sync)
-                 * before we can safely let the old group leader die.
-                 */
-                sig->tsk = tsk;
-                spin_unlock_irq(lock);
-                if (hrtimer_cancel(&sig->real_timer))
-                        hrtimer_restart(&sig->real_timer);
-                spin_lock_irq(lock);
-        }
-
+        /* Account for the thread group leader hanging around: */
+        count = thread_group_leader(tsk) ? 1 : 2;
         sig->notify_count = count;
         while (atomic_read(&sig->count) > count) {
                 __set_current_state(TASK_UNINTERRUPTIBLE);