systemd/1011-check-4-valid-kmsg-device.patch

From: Werner Fink <werner@suse.de>
Date: Thu, 21 Nov 2013 11:50:32 +0000
Subject: [PATCH] Avoid busy systemd-journald

Avoid a busy systemd-journald due polling a broken /dec/kmsg in lxc
environments.

---
 journald-kmsg.c |   18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

Index: systemd-208/src/journal/journald-kmsg.c
===================================================================
--- systemd-208/src/journal/journald-kmsg.c
+++ systemd-208/src/journal/journald-kmsg.c	2013-12-20 11:34:39.762236175 +0000
@@ -377,15 +377,18 @@ int server_flush_dev_kmsg(Server *s) {
 
 int server_open_dev_kmsg(Server *s) {
         struct epoll_event ev;
+        int r;
 
         assert(s);
 
         s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
         if (s->dev_kmsg_fd < 0) {
-                log_warning("Failed to open /dev/kmsg, ignoring: %m");
+                log_full(errno == ENOENT ? LOG_DEBUG : LOG_WARNING,
+                         "Failed to open /dev/kmsg, ignoring: %m");
                 return 0;
         }
 
+        r = 0;
         zero(ev);
         ev.events = EPOLLIN;
         ev.data.fd = s->dev_kmsg_fd;
@@ -394,15 +397,24 @@ int server_open_dev_kmsg(Server *s) {
                 /* This will fail with EPERM on older kernels where
                  * /dev/kmsg is not readable. */
                 if (errno == EPERM)
-                        return 0;
+                        goto fail;
 
                 log_error("Failed to add /dev/kmsg fd to epoll object: %m");
-                return -errno;
+                r = -errno;
+                goto fail;
         }
 
         s->dev_kmsg_readable = true;
 
         return 0;
+
+fail:
+        if (s->dev_kmsg_fd >= 0) {
+                close_nointr_nofail(s->dev_kmsg_fd);
+                s->dev_kmsg_fd = -1;
+        }
+
+        return r;
 }
 
 int server_open_kernel_seqnum(Server *s) {