Re: multifd/tcp/zlib intermittent abort (was: Re: [PULL 00/18] migration queue)

[Peter Maydell]

On Tue, 15 Mar 2022 at 15:03, Peter Maydell <peter.maydell@linaro.org> wrote:
> Maybe we're running into this bug
> https://bugs.launchpad.net/ubuntu/+source/zlib/+bug/1961427
> ("zlib: compressBound() returns an incorrect result on z15") ?

Full repro info, since it's a bit hidden in this long thread:

Build an i386 guest QEMU; I used this configure command:

'../../configure' '--target-list=i386-softmmu' '--enable-debug'
'--with-pkgversion=pm215' '--disable-docs'

Then run the multifd/tcp/zlib test in a tight loop:

X=1; while QTEST_QEMU_BINARY=./build/i386/i386-softmmu/qemu-system-i386
./build/i386/tests/qtest/migration-test  -tap -k -p
/i386/migration/multifd/tcp/zlib ; do echo $X; X=$((X+1)); done

Without DFLTCC=0 it fails typically within 5 or so iterations;
the longest I've ever seen it go is about 32.

-- PMM