From 24122c7f4969adeeaeca3fb1656a31569e9aa59b Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 20 Jul 2018 14:30:23 -0500 Subject: signal: Pass pid and pid type into send_sigqueue Make the code more maintainable by performing more of the signal related work in send_sigqueue. A quick inspection of do_timer_create will show that this code path does not lookup a thread group by a thread's pid. Making it safe to find the task pointed to by it_pid with "pid_task(it_pid, type)"; This supports the changes needed in fork to tell if a signal was sent to a single process or a group of processes. Having the pid to task transition in signal.c will also make it easier to sort out races with de_thread and and the thread group leader exiting when it comes time to address that. Signed-off-by: "Eric W. Biederman" --- kernel/signal.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 8d8a940422a8..40feb14e276d 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1664,17 +1664,20 @@ void sigqueue_free(struct sigqueue *q) __sigqueue_free(q); } -int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) +int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) { int sig = q->info.si_signo; struct sigpending *pending; + struct task_struct *t; unsigned long flags; int ret, result; BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); ret = -1; - if (!likely(lock_task_sighand(t, &flags))) + rcu_read_lock(); + t = pid_task(pid, type); + if (!t || !likely(lock_task_sighand(t, &flags))) goto ret; ret = 1; /* the signal is ignored */ @@ -1696,15 +1699,16 @@ int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) q->info.si_overrun = 0; signalfd_notify(t, sig); - pending = group ? &t->signal->shared_pending : &t->pending; + pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; list_add_tail(&q->list, &pending->list); sigaddset(&pending->signal, sig); - complete_signal(sig, t, group); + complete_signal(sig, t, type != PIDTYPE_PID); result = TRACE_SIGNAL_DELIVERED; out: - trace_signal_generate(sig, &q->info, t, group, result); + trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result); unlock_task_sighand(t, &flags); ret: + rcu_read_unlock(); return ret; } -- cgit v1.2.3