[master] bbf4942 Restore SIGSEGV and SIGABRT to SIG_DFL in child_signal_handler() to prevent recursion.

[Poul-Henning Kamp]

commit bbf494287fd5de02f7eecd71564f142af22a0876
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Tue Aug 29 07:45:40 2017 +0000

    Restore SIGSEGV and SIGABRT to SIG_DFL in child_signal_handler()
    to prevent recursion.

diff --git a/bin/varnishd/mgt/mgt_child.c b/bin/varnishd/mgt/mgt_child.c
index 91d6c5e..3e30dda 100644
--- a/bin/varnishd/mgt/mgt_child.c
+++ b/bin/varnishd/mgt/mgt_child.c
@@ -263,9 +263,16 @@ static void __match_proto__()
 child_signal_handler(int s, siginfo_t *si, void *c)
 {
 	char buf[1024];
+	struct sigaction sa;
 
 	(void)c;
 
+	/* Don't come back */
+	memset(&sa, 0, sizeof sa);
+	sa.sa_handler = SIG_DFL;
+	(void)sigaction(SIGSEGV, &sa, NULL);
+	(void)sigaction(SIGABRT, &sa, NULL);
+
 	bprintf(buf, "Signal %d (%s) received at %p si_code %d",
 		s, strsignal(s), si->si_addr, si->si_code);
 	VAS_Fail(__func__,