From 2c4d473560b29aa6a3ee48faa07c3fe9e90dae7e Mon Sep 17 00:00:00 2001
From: Ruediger Oertel <ro@suse.de>
Date: Fri, 13 Jun 2014 16:41:06 +0200
Subject: [PATCH] Reset signal-mask on re-exec to init=..

Process 1 (aka init) needs to be started with an empty signal mask.
That includes the process 1 that's started after the initrd is finished.
When the initrd is using systemd (as it does with dracut based initrds)
then it is systemd that calls the real init.  Normally this is systemd
again, except when the user uses for instance "init=/bin/bash" on the
kernel command line.

(cherry picked from commit 5a85ca1cb622fda4a39c8a6f00dccea7f8a1e82a)
(cherry picked from commit 3eb31d88fd664d55251102d8504d05426a97d0b3)
---
 src/core/main.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/core/main.c b/src/core/main.c
index 2a294c67fb..2f4548502f 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -1748,6 +1748,7 @@ finish:
         if (reexecute) {
                 const char **args;
                 unsigned i, args_size;
+                sigset_t ss, o_ss;
 
                 /* Close and disarm the watchdog, so that the new
                  * instance can reinitialize it, but doesn't get
@@ -1831,6 +1832,11 @@ finish:
                 args[i++] = NULL;
                 assert(i <= args_size);
 
+                /* reenable any blocked signals, especially important
+                 * if we switch from initial ramdisk to init=... */
+                sigemptyset(&ss);
+                sigprocmask(SIG_SETMASK, &ss, &o_ss);
+
                 if (switch_root_init) {
                         args[0] = switch_root_init;
                         execv(args[0], (char* const*) args);
@@ -1849,6 +1855,8 @@ finish:
                         log_error("Failed to execute /bin/sh, giving up: %m");
                 } else
                         log_warning("Failed to execute /sbin/init, giving up: %m");
+
+                sigprocmask(SIG_SETMASK, &o_ss, NULL);
         }
 
         if (serialization)