[uml-devel] Re: handle_trap - failed to wait at end of syscall [was Re: [uml- devel] debugging UML cores]

[Joe Marzot <gmarzot@nortelnetworks.com>]

Jeff Dike wrote:
> gmarzot@nortelnetworks.com said:
>  > WSTOPSIG(err) = SIGHUP
>  > does this give any clues...any ideas of what else to look at?
> 
> Do you have any idea how you're making this happen? 

unfortunately not...the UML instance is being used as a test harness for 
a complex set of interacting processes. all sorts of things are going 
prior to the crash.

> The userspace 
> process is
> getting a SIGHUP in the middle of having a system call nullified.  

what does it mean to nullify a system call?

I am also losing whether this is a simulated signal inside the UML 
userspace app or a host signal being delivered to the host resident UML 
usespace thread.

> This is OK
> since a SIGHUP can happen any time if you log out on it or something, but
> I'd like to know exactly what's going on so I can decide what the right 
> reaction
> to it is.

as it is a test harness there are lot's of scripts being invoked - 
shells are being spawned and exited. There may be expect scripts logging 
into the UML and logging out if that's what mean.

> 
> Simplistically, we could just handle it there and ignore it, since UML 
> probably
> got the SIGHUP as well, and will deal with it then.

something like this?

if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP) || 
(WSTOPSIG(status) != SIGHUP)) {
    ....
} else {
    handle_syscall(regs);
}

regards, GSM

> 
>                                 Jeff
> 
> 
> 





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