Make sure to reset the signal handler and deliver again the original crashing...

Make sure to reset the signal handler and deliver again the original crashing signal when dumping the stack trace. This will allow to dump the core if core dumping is enabled.

src/redis.c

@@ -1606,6 +1606,7 @@ void segvHandler(int sig, siginfo_t *info, void *secret) {
     int i, trace_size = 0;
     ucontext_t *uc = (ucontext_t*) secret;
     sds infostring;
+    struct sigaction act;
     REDIS_NOTUSED(info);
 
     redisLog(REDIS_WARNING,
@@ -1627,7 +1628,16 @@ void segvHandler(int sig, siginfo_t *info, void *secret) {
 
     /* free(messages); Don't call free() with possibly corrupted memory. */
     if (server.daemonize) unlink(server.pidfile);
-    _exit(0);
+
+    /* Make sure we exit with the right signal at the end. So for instance
+     * the core will be dumped if enabled. */
+    sigemptyset (&act.sa_mask);
+    /* When the SA_SIGINFO flag is set in sa_flags then sa_sigaction
+     * is used. Otherwise, sa_handler is used */
+    act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
+    act.sa_handler = SIG_DFL;
+    sigaction (sig, &act, NULL);
+    kill(getpid(),sig);
 }
 
 void sigtermHandler(int sig) {