Re: [Qemu-devel] [PATCH for-3.0] tests/libqtest: Improve kill_qemu() assert

[Eric Blake <eblake@redhat.com>]

On 07/23/2018 01:47 PM, Peter Maydell wrote:
> In kill_qemu() we have an assert that checks that the QEMU process
> didn't dump core:
>              assert(!WCOREDUMP(wstatus));
> 
> Unfortunately the WCOREDUMP macro here means the resulting message
> is not very easy to comprehend on at least some systems:
> 
> ahci-test: tests/libqtest.c:113: kill_qemu: Assertion `!(((__extension__ (((union { __typeof(wstatus) __in; int __i; }) { .__in = (wstatus) }).__i))) & 0x80)' failed.
> 
> and it doesn't identify what signal the process took.
> 
> Instead of using a raw assert, print the information in an
> easier to understand way:
> 
> /i386/ahci/sanity: tests/libqtest.c:119: kill_qemu() tried to terminate QEMU process but it dumped core with signal 11 (Segmentation fault)
> Aborted (core dumped)
> 
> (Of course, the really useful information would be why the QEMU
> process dumped core in the first place, but we don't have that
> by the time the test program has picked up the exit status.)

Last time we bike-shedded this, I suggested that we fix things to call 
waitpid() in a loop, and that we just assert that exit status is 0:

https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg05610.html

In other words, why are we special-casing death-by-coredump, when ALL 
non-zero exit status (whether or not a core dump was involved) is 
contrary to the assumptions of the testsuite?

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org