Re: [Qemu-devel] Qemu hanging

[Alex Bennée]

Filipe Manana <address@hidden> writes:

> Hello,
>
> Recently qemu started hanging when running fstests (xfstests) after
> upgrading the guests kernel (linux) from 4.15.x to 4.16. Nothing else
> changed in the host or guest, besides the kernel version in the guest.
>
> Running fstests always hangs when running either the test generic/299
> or generic/451. But it happens only when running all the generic tests
> in sequence, running any of those two tests in isolation doesn't hang
> qemu (so far at least).
>
> I tried with qemu versions 2.11.2,  2.12.1 and 3.0.0. It hangs with
> any of these versions. The issue happens with any linux kernel version
>>= 4.16 (including latest 4.19-rc5) in the guest.
> Initially I noticed this when testing btrfs with fstests but later
> checked that it happens as well when testing xfs.
>
> I captured a coredump (using qemu 3.0.0) and it's available at:
>
> https://www.dropbox.com/s/c3ntm5galaz4r83/core_dump.tar.xz?dl=0
>
> The stack traces of all the qemu threads are pasted here (not every helpful):
>
> https://friendpaste.com/hmCX2IG3VrA233uNtw1MP

If you can rebuild with:

  ./configure --enable-debug --extra-cflags="-O0 -g3 -fno-omit-frame-pointer"

You should be able to get more useful backtraces (and core-dumps).

>
> This happens on 2 different physical machines (x86_64, running
> different linux distros with different kernel versions) even when
> using new guests.
>
> qemu is invoked with the following script/config:
>
> https://friendpaste.com/hmCX2IG3VrA233uNuFRNc
>
> Anything else I can provide to help debug this?
>
> Thanks.


--
Alex Bennée