[LTP] Question regarding background jobs in LTP

[LTP] Question regarding background jobs in LTP

[Elif Aslan]

We've found an issue when executing our testcase mon_fsstatd under LTP. 
The test logic assumes that we start some processes as shell jobs and then kill them, like in these commands

    mon_fsstatd_run 0 "mon_procd -a &"
    sleep 2
    mon_fsstatd_run 0 "killall mon_procd"

But so far we observe that the testcase being run as 
./runltp -f s390x_tests
simply hangs at the point of starting background job, it simply runs in foreground, and then test finishes with error after timeout.

Is it possible to execute background jobs in LTP ?

[LTP] Question regarding background jobs in LTP

[Cyril Hrubis]

Hi!
> We've found an issue when executing our testcase mon_fsstatd under LTP. 
> The test logic assumes that we start some processes as shell jobs and then kill them, like in these commands
> 
>     mon_fsstatd_run 0 "mon_procd -a &"
>     sleep 2
>     mon_fsstatd_run 0 "killall mon_procd"
> 
> But so far we observe that the testcase being run as 
> ./runltp -f s390x_tests
> simply hangs at the point of starting background job, it simply runs in foreground, and then test finishes with error after timeout.
> 
> Is it possible to execute background jobs in LTP ?

It should be possible unless the command you are trying to run needs
access to stdin since that could be done only by the process group
leader which is always the ltp-pan binary.

From the snippet of code it's not 100% clear what the code does, can you
share at least the code for mon_fsstad_run function? Also have you tried
to change the shebang to #!/bin/sh -x to see where exactly it hangs?

-- 
Cyril Hrubis
chrubis@suse.cz

[LTP] Question regarding background jobs in LTP

[Elif Aslan]

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Hi, 
please find in attachment the script.

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We've tried  "#/bin/sh -x" didn't changed the output
it hangs on the same command:

mon_fsstatd 1 TPASS: 'mon_procd --version' returned '0'
mon_fsstatd 1 TPASS: 'mon_procd -i 30' returned '0'
mon_fsstatd 1 TBROK: test killed, timeout!
the command which lead to the hang - is the same:

mon_fsstatd_run 0 "mon_procd -a &”

---
Elif Aslan

> On 1. Mar 2019, at 12:49, Cyril Hrubis <chrubis@suse.cz> wrote:
> 
> Hi!
>> We've found an issue when executing our testcase mon_fsstatd under LTP. 
>> The test logic assumes that we start some processes as shell jobs and then kill them, like in these commands
>> 
>>    mon_fsstatd_run 0 "mon_procd -a &"
>>    sleep 2
>>    mon_fsstatd_run 0 "killall mon_procd"
>> 
>> But so far we observe that the testcase being run as 
>> ./runltp -f s390x_tests
>> simply hangs at the point of starting background job, it simply runs in foreground, and then test finishes with error after timeout.
>> 
>> Is it possible to execute background jobs in LTP ?
> 
> It should be possible unless the command you are trying to run needs
> access to stdin since that could be done only by the process group
> leader which is always the ltp-pan binary.
> 
> From the snippet of code it's not 100% clear what the code does, can you
> share at least the code for mon_fsstad_run function? Also have you tried
> to change the shebang to #!/bin/sh -x to see where exactly it hangs?
> 
> -- 
> Cyril Hrubis
> chrubis@suse.cz
> 

[LTP] Question regarding background jobs in LTP

[Cyril Hrubis]

Hi!
> We've tried  "#/bin/sh -x" didn't changed the output
> it hangs on the same command:
> 
> mon_fsstatd 1 TPASS: 'mon_procd --version' returned '0'
> mon_fsstatd 1 TPASS: 'mon_procd -i 30' returned '0'
> mon_fsstatd 1 TBROK: test killed, timeout!
> the command which lead to the hang - is the same:
> 
> mon_fsstatd_run 0 "mon_procd -a &???

Now I see the problem, you cannot pass a string to a function, execute
the variable holding the string, and expect bash to parse special
characters in the string, as it is the & is passed as a parameter to the
mon_procd instead because the string is not broken down.

-- 
Cyril Hrubis
chrubis@suse.cz