From: Oleg Nesterov 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 Acked-by: "Eric W. Biederman" Cc: Davide Libenzi Cc: Pavel Emelyanov Acked-by: Roland McGrath Acked-by: Thomas Gleixner Signed-off-by: Andrew Morton --- fs/exec.c | 22 ++-------------------- include/linux/sched.h | 3 +-- kernel/fork.c | 2 +- kernel/itimer.c | 2 +- kernel/signal.c | 14 -------------- 5 files changed, 5 insertions(+), 38 deletions(-) diff -puN fs/exec.c~itimer_real-convert-to-use-struct-pid fs/exec.c --- a/fs/exec.c~itimer_real-convert-to-use-struct-pid +++ a/fs/exec.c @@ -782,26 +782,8 @@ static int de_thread(struct task_struct 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); diff -puN include/linux/sched.h~itimer_real-convert-to-use-struct-pid include/linux/sched.h --- a/include/linux/sched.h~itimer_real-convert-to-use-struct-pid +++ a/include/linux/sched.h @@ -453,7 +453,7 @@ struct signal_struct { /* ITIMER_REAL timer for the process */ struct hrtimer real_timer; - struct task_struct *tsk; + struct pid *leader_pid; ktime_t it_real_incr; /* ITIMER_PROF and ITIMER_VIRTUAL timers for the process */ @@ -1663,7 +1663,6 @@ extern void block_all_signals(int (*noti extern void unblock_all_signals(void); extern void release_task(struct task_struct * p); extern int send_sig_info(int, struct siginfo *, struct task_struct *); -extern int send_group_sig_info(int, struct siginfo *, struct task_struct *); extern int force_sigsegv(int, struct task_struct *); extern int force_sig_info(int, struct siginfo *, struct task_struct *); extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp); diff -puN kernel/fork.c~itimer_real-convert-to-use-struct-pid kernel/fork.c --- a/kernel/fork.c~itimer_real-convert-to-use-struct-pid +++ a/kernel/fork.c @@ -883,7 +883,6 @@ static int copy_signal(unsigned long clo hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); sig->it_real_incr.tv64 = 0; sig->real_timer.function = it_real_fn; - sig->tsk = tsk; sig->it_virt_expires = cputime_zero; sig->it_virt_incr = cputime_zero; @@ -1308,6 +1307,7 @@ static struct task_struct *copy_process( if (clone_flags & CLONE_NEWPID) p->nsproxy->pid_ns->child_reaper = p; + p->signal->leader_pid = pid; p->signal->tty = current->signal->tty; set_task_pgrp(p, task_pgrp_nr(current)); set_task_session(p, task_session_nr(current)); diff -puN kernel/itimer.c~itimer_real-convert-to-use-struct-pid kernel/itimer.c --- a/kernel/itimer.c~itimer_real-convert-to-use-struct-pid +++ a/kernel/itimer.c @@ -132,7 +132,7 @@ enum hrtimer_restart it_real_fn(struct h struct signal_struct *sig = container_of(timer, struct signal_struct, real_timer); - send_group_sig_info(SIGALRM, SEND_SIG_PRIV, sig->tsk); + kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid); return HRTIMER_NORESTART; } diff -puN kernel/signal.c~itimer_real-convert-to-use-struct-pid kernel/signal.c --- a/kernel/signal.c~itimer_real-convert-to-use-struct-pid +++ a/kernel/signal.c @@ -1204,20 +1204,6 @@ send_sig(int sig, struct task_struct *p, return send_sig_info(sig, __si_special(priv), p); } -/* - * This is the entry point for "process-wide" signals. - * They will go to an appropriate thread in the thread group. - */ -int -send_group_sig_info(int sig, struct siginfo *info, struct task_struct *p) -{ - int ret; - read_lock(&tasklist_lock); - ret = group_send_sig_info(sig, info, p); - read_unlock(&tasklist_lock); - return ret; -} - void force_sig(int sig, struct task_struct *p) { _