[Libguestfs] Unknown libguestfs failure / race

[Richard W.M. Jones]

On Thu, Aug 27, 2020 at 03:59:30PM +0300, Sam Eiderman wrote:
> 2020-08-27 08:48:40 T libguestfs - 0 - appliance - Term: 80x24
> 2020-08-27 08:48:40 T libguestfs - 0 - appliance - 4 0
> 2020-08-27 08:48:40 T libguestfs - 0 - appliance - ^[[2J
> 2020-08-27 08:48:40 T libguestfs - 0 - appliance - SeaBIOS (version 1.12.0-1)
> 2020-08-27 08:48:40 T libguestfs - 0 - appliance - Booting from ROM...
> 2020-08-27 08:48:40 T libguestfs - 0 - library - child_cleanup:
> 0xd5a840: child process died
...
> It seems that the qemu process has died somewhere between the ROM boot
> and the kernel loading.
> 
> Any ideas how to debug this?

qemu failures are the worst ...

First of all, enable core dumps.  Maybe qemu is dumping core, and if
it is then (a) it's a qemu bug and (b) the core dump will tell you (or
the qemu developers) exactly what's wrong.

Also look at the host dmesg.  Since you're starting many instances of
qemu it might be that the host is running out of memory, or there's
another kernel resource being exhausted.  The kernel will print
something if that happens.

It's also probably best to try to get a reproducer using
libguestfs-test-tool in a loop (or more likely, 16 loops all running
libguestfs-test-tool as fast as they can).

Rich.

-- 
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