signals: allow the kernel to actually kill /sbin/init (80fe728d) · Commits · 戴 / test

Currently the buggy /sbin/init hangs if SIGSEGV/etc happens. The kernel sends the signal, init dequeues it and ignores, returns from the exception, repeats the faulting instruction, and so on forever. Imho, such a behaviour is not good. I think that the explicit loud death of the buggy /sbin/init is better than the silent hang. Change force_sig_info() to clear SIGNAL_UNKILLABLE when the task should be really killed. 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

+4 −1

Original line number	Diff line number	Diff line
		@@ -892,7 +892,8 @@ specific_send_sig_info(int sig, struct siginfo info, struct task_struct t)
		* since we do not want to have a signal handler that was blocked
		* be invoked when user space had explicitly blocked it.
		*
		* We don't want to have recursive SIGSEGV's etc, for example.
		* We don't want to have recursive SIGSEGV's etc, for example,
		* that is why we also clear SIGNAL_UNKILLABLE.
		*/
		int
		force_sig_info(int sig, struct siginfo info, struct task_struct t)
		@@ -912,6 +913,8 @@ force_sig_info(int sig, struct siginfo info, struct task_struct t)
		recalc_sigpending_and_wake(t);
		}
		}
		if (action->sa.sa_handler == SIG_DFL)
		t->signal->flags &= ~SIGNAL_UNKILLABLE;
		ret = specific_send_sig_info(sig, info, t);
		spin_unlock_irqrestore(&t->sighand->siglock, flags);

Admin message