[dm-devel] [PATCH v2 2/2] multipathd: handle errors in uxlsnr as fatal

[Martin Wilck]

The ppoll() calls of the uxlsnr thread are vital for proper functioning of
multipathd. If the uxlsnr thread can't open the socket or fails to call ppoll()
for other reasons, quit the daemon. If we don't do that, multipathd may
hang in a state where it can't be terminated any more, because the uxlsnr
thread is responsible for handling all signals. This happens e.g. if
systemd's multipathd.socket is running in and multipathd is started from
outside systemd.

24f2844 "multipathd: fix signal blocking logic" has made this problem more
severe. Before that patch, the signals weren't actually blocked in any thread.
That's not to say 24f2844 was wrong. I still think it's correct, we just
need this one on top.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 multipathd/uxlsnr.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/multipathd/uxlsnr.c b/multipathd/uxlsnr.c
index cdafd82943e7..6f666663fc6f 100644
--- a/multipathd/uxlsnr.c
+++ b/multipathd/uxlsnr.c
@@ -178,7 +178,7 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
 
 	if (ux_sock == -1) {
 		condlog(1, "could not create uxsock: %d", errno);
-		return NULL;
+		exit_daemon();
 	}
 
 	pthread_cleanup_push(uxsock_cleanup, (void *)ux_sock);
@@ -187,7 +187,7 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
 	polls = (struct pollfd *)MALLOC((MIN_POLLS + 1) * sizeof(struct pollfd));
 	if (!polls) {
 		condlog(0, "uxsock: failed to allocate poll fds");
-		return NULL;
+		exit_daemon();
 	}
 	sigfillset(&mask);
 	sigdelset(&mask, SIGINT);
@@ -249,6 +249,7 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
 
 			/* something went badly wrong! */
 			condlog(0, "uxsock: poll failed with %d", errno);
+			exit_daemon();
 			break;
 		}
 
-- 
2.16.1