From 6a50c735a3bbf98d06fbfa7815f7bdc14ea96f9f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Wed, 14 Oct 2020 14:03:13 +0200
Subject: [PATCH] sd-bus: break the loop in bus_ensure_running() if the bus is
 not connecting

This might fix #17025:
> the call trace is
> bus_ensure_running -> sd_bus_process -> bus_process_internal -> process_closeing --> sd_bus_close
>                                                                                  |
>                                                                                  \-> process_match

We ended doing callouts to the Disconnected matches from bus_ensure_running()
and shouldn't. bus_ensure_running() should never do callouts. This change
should fix this however: once we notice that the connection is going down we
will now fail instantly with ENOTOCONN instead of calling any callbacks.

(cherry picked from commit 93a59b1ae5d3bcb0ec1488ebc13d0d1ff4d1729a)

Resolves: #1885553
---
 src/libsystemd/sd-bus/sd-bus.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index a3509f7e89..c65e24b2d1 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -2059,12 +2059,13 @@ int bus_ensure_running(sd_bus *bus) {
 
         assert(bus);
 
-        if (IN_SET(bus->state, BUS_UNSET, BUS_CLOSED, BUS_CLOSING))
-                return -ENOTCONN;
         if (bus->state == BUS_RUNNING)
                 return 1;
 
         for (;;) {
+                if (IN_SET(bus->state, BUS_UNSET, BUS_CLOSED, BUS_CLOSING))
+                        return -ENOTCONN;
+
                 r = sd_bus_process(bus, NULL);
                 if (r < 0)
                         return r;