From 59bce92b081cf0b52c4335461af7cbd003a11aeb Mon Sep 17 00:00:00 2001
From: chenglin130 <cheng.lin130@zte.com.cn>
Date: Sat, 9 Nov 2019 23:04:04 +0800
Subject: [PATCH] core: coldplug possible nop_job

When a unit in a state INACTIVE or DEACTIVATING, JobType JOB_TRY_RESTART or
JOB_TRY_RELOAD will be collapsed to JOB_NOP. And use u->nop_job instead
of u->job.

If a JOB_NOP job is going on with a waiting state, a parallel daemon-reload
just install it during deserialization. Without a coldplug, the job will
not be in m->run_queue, which results in a hung try-restart or
try-reload process.

Reproduce:
1. run systemctl try-restart test.servcie (inactive) repeatly in a terminal.
2. run systemctl daemon-reload repeatly in other terminals.

After successful reproduce, systemctl list-jobs will list the hang job.

Upsteam:
https://github.com/systemd/systemd/pull/13124

(cherry picked from commit 8ee652948b0255005e4c9d278ac06b30711d9dbd)

Resolves: #1847336
---
 src/core/unit.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/core/unit.c b/src/core/unit.c
index dc2df4c89c..856ebf3e64 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2900,6 +2900,7 @@ static int unit_add_deserialized_job_coldplug(Unit *u) {
 
 int unit_coldplug(Unit *u, Hashmap *deferred_work) {
         int r;
+        Job *uj;
 
         assert(u);
 
@@ -2907,8 +2908,9 @@ int unit_coldplug(Unit *u, Hashmap *deferred_work) {
                 if ((r = UNIT_VTABLE(u)->coldplug(u, deferred_work)) < 0)
                         return r;
 
-        if (u->job) {
-                r = job_coldplug(u->job);
+        uj = u->job ?: u->nop_job;
+        if (uj) {
+                r = job_coldplug(uj);
                 if (r < 0)
                         return r;
         } else if (u->deserialized_job >= 0)