signals: use __group_complete_signal() for the specific signals too (5fcd835b) · Commits · 戴 / test

Based on Pavel Emelyanov's suggestion. Rename __group_complete_signal() to complete_signal() and use it to process the specific signals too. To do this we simply add the "int group" argument. This allows us to greatly simply the signal-sending code and adds a useful behaviour change. We can avoid the unneeded wakeups for the private signals because wants_signal() is more clever than sigismember(blocked), but more importantly we now take into account the fatal specific signals too. The latter allows us to kill some subtle checks in handle_stop_signal() and makes the specific/group signal's behaviour more consistent. For example, currently sigtimedwait(FATAL_SIGNAL) behaves differently depending on was the signal sent by kill() or tkill() if the signal was not blocked. And. This allows us to tweak/fix the behaviour when the specific signal is sent to the dying/dead ->group_leader. Signed-off-by:

Pavel Emelyanov <xemul@openvz.org> Signed-off-by:

Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

kernel/signal.c

+6 −9

Original line number	Diff line number	Diff line
		@@ -673,8 +673,7 @@ static inline int wants_signal(int sig, struct task_struct *p)
		return task_curr(p) \|\| !signal_pending(p);
		}

		static void
		__group_complete_signal(int sig, struct task_struct *p)
		static void complete_signal(int sig, struct task_struct *p, int group)
		{
		struct signal_struct *signal = p->signal;
		struct task_struct *t;
		@@ -687,7 +686,7 @@ __group_complete_signal(int sig, struct task_struct *p)
		*/
		if (wants_signal(sig, p))
		t = p;
		else if (thread_group_empty(p))
		else if (!group \|\| thread_group_empty(p))
		/*
		* There is just one thread and it does not need to be woken.
		* It will dequeue unblocked signals before it runs again.
		@@ -871,8 +870,7 @@ specific_send_sig_info(int sig, struct siginfo info, struct task_struct t)
		if (ret <= 0)
		return ret;

		if (!sigismember(&t->blocked, sig))
		signal_wake_up(t, sig == SIGKILL);
		complete_signal(sig, t, 0);
		return 0;
		}

		@@ -930,7 +928,7 @@ __group_send_sig_info(int sig, struct siginfo info, struct task_struct p)
		if (ret <= 0)
		return ret;

		__group_complete_signal(sig, p);
		complete_signal(sig, p, 1);
		return 0;
		}

		@@ -1309,8 +1307,7 @@ int send_sigqueue(int sig, struct sigqueue q, struct task_struct p)

		ret = do_send_sigqueue(sig, q, p, 0);

		if (!sigismember(&p->blocked, sig))
		signal_wake_up(p, sig == SIGKILL);
		complete_signal(sig, p, 0);

		unlock_task_sighand(p, &flags);
		out_err:
		@@ -1330,7 +1327,7 @@ send_group_sigqueue(int sig, struct sigqueue q, struct task_struct p)

		ret = do_send_sigqueue(sig, q, p, 1);

		__group_complete_signal(sig, p);
		complete_signal(sig, p, 1);

		spin_unlock_irqrestore(&p->sighand->siglock, flags);

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