[Bug 703800] Re: restart command fails to restart main process when pre-stop stanza exists
Having found another instance of this problem, the powernap package in Ubuntu, I am marking this as Confirmed in Upstart, and Triaged in Ubuntu. ** Changed in: upstart Status: New = Confirmed ** Changed in: upstart (Ubuntu) Status: New = Confirmed ** Changed in: upstart (Ubuntu) Importance: Undecided = Medium ** Changed in: upstart (Ubuntu) Status: Confirmed = Triaged -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/703800 Title: restart command fails to restart main process when pre-stop stanza exists -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 703800] Re: restart command fails to restart main process when pre-stop stanza exists
I can confirm I see this behavior in upstart (0.6.5-8) on lucid. On several of our custom tasks, if I change pre-stop to post-stop, then restart behaves normally. I will see if I can craft an upstart job to mimic this behavior using stock tools. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/703800 Title: restart command fails to restart main process when pre-stop stanza exists -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 703800] Re: restart command fails to restart main process when pre-stop stanza exists
Yeah there are quite a few bugs related to pre-stop scripts, they don't really work like any other, so there are definite gaps in the coverage On Thu, Feb 24, 2011 at 8:00 AM, scm 703...@bugs.launchpad.net wrote: I can confirm I see this behavior in upstart (0.6.5-8) on lucid. On several of our custom tasks, if I change pre-stop to post-stop, then restart behaves normally. I will see if I can craft an upstart job to mimic this behavior using stock tools. -- You received this bug notification because you are a member of Upstart Developers, which is subscribed to upstart . https://bugs.launchpad.net/bugs/703800 Title: restart command fails to restart main process when pre-stop stanza exists Status in Upstart: New Status in “upstart” package in Ubuntu: New Bug description: While testing the portmap daemon's recent changes in Ubuntu which cause statd to properly follow it on stop/start, I tried to restart portmap, only to find that it was not in fact restarted. This happens with any job that has a pre-stop. The reason is that in job_restart(), the code does this: job_change_goal (job, JOB_STOP); job_change_goal (job, JOB_START); job_change_goal will return as soon as the *first* state change has been completed. If there is no pre-stop, that is the change from JOB_RUNNING to JOB_KILLED, which does dutifully kill the main process. However, if there is a pre-stop, the pre-stop is run, but then job_change_state returns to job_change_goal, which then returns to job_restart, which then changes the goal back to start, which makes the new job_next_state() one that will bypass the change to JOB_KILLED. This was found on upstart v0.6.7-3 in Ubuntu, but also exists in the code in the current trunk. TEST CASE 1. create job file /etc/init/test-restart-prestop.conf with this content: # test-restart-prestop pre-stop exec /bin/true exec /bin/sleep 3600 2. run start test-restart-prestop -- record pid of job 3. immediately run restart test-restart-prestop -- if bug is present, pid remains the same when it should be a new pid. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/703800 Title: restart command fails to restart main process when pre-stop stanza exists -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 703800] Re: restart command fails to restart main process when pre-stop stanza exists
** Tags added: glucid lucid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/703800 Title: restart command fails to restart main process when pre-stop stanza exists -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 703800] Re: restart command fails to restart main process when pre-stop stanza exists
On further investigation, this does *not* affect jobs that block the
'stopping' event. So I believe this may be related more to the way
job_process_run treates pre-stop. According to comments in
init/job_process.c:
/* We don't change the state if we're in post-start and there's
* a post-start process running, or if we're in pre-stop and
* there's a pre-stop process running; we wait for those to
* finish instead.
*/
if ((job-state == JOB_POST_START)
job-class-process[PROCESS_POST_START]
(job-pid[PROCESS_POST_START] 0)) {
state = FALSE;
} else if ((job-state == JOB_PRE_STOP)
job-class-process[PROCESS_PRE_STOP]
(job-pid[PROCESS_PRE_STOP] 0)) {
state = FALSE;
}
Later on, if (!state) calls job_change_goal(job, JOB_RESPAWN) ..
Digging into job_next_state a bit, I found that a goal of JOB_RESPAWN
causes job_next_state to change the goal only if state is JOB_POST_START
or JOB_PRE_STOP. JOB_POST_START changes the goal to JOB_START, which
makes sense. But JOB_PRE_STOP changes the goal to JOB_START as well!
This doesn't make much sense to me, and I thought the obvious fix would
be to change it to be JOB_STOP, however this caused test_job to fail
here:
...with post-start job and a goal of respawn
BAD: wrong value for job-goal, expected 1 got 0
at tests/test_job.c:4129 (test_next_state).
/bin/bash: line 5: 29784 Aborted ${dir}$tst
FAIL: test_job
This was confusing until I realized that the test code is wrong:
/* Check that the next state if we're respawning after a pre-stop
* job is stopping with the goal changed.
*/
TEST_FEATURE (with post-start job and a goal of respawn);
job-goal = JOB_RESPAWN;
job-state = JOB_PRE_STOP;
TEST_EQ (job_next_state (job), JOB_STOPPING);
TEST_EQ (job-goal, JOB_START);
That should read 'with pre-stop job and a goal of respawn'.
So, this brings to the edge case that I think is causing this problem,
and my perceived fix.
If you want a running job to be restarted, it should move from wherever
it was, through stopping-pre-stop-killed-post-stop-starting- ...
However, this doesn't happen. Instead the goal is changed to STOP, but
job_change_goal() does not wait for that to happen, which its docblock
would suggest.
Instead, it returns with the state set to JOB_PRE_STOP ..
This is my proposed fix.. though I'm not entirely confident this is the
right way to handle it, and I haven't had a chance to test this yet.
=== modified file 'init/job.c'
--- init/job.c 2010-12-14 15:32:41 +
+++ init/job.c 2011-01-17 07:56:24 +
@@ -1265,6 +1265,12 @@
nih_list_add (job-blocking, blocked-entry);
job_change_goal (job, JOB_STOP);
+if (job-state == JOB_PRE_STOP)
+{
+ /* hack: should not happen but does */
+ job-goal = JOB_RESPAWN;
+ job_change_goal (job, JOB_STOP);
+}
job_change_goal (job, JOB_START);
if (! wait)
--
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https://bugs.launchpad.net/bugs/703800
Title:
restart command fails to restart main process when pre-stop stanza
exists
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