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

[Daniel P . Berrangé]

On Tue, Mar 15, 2022 at 03:30:27PM +0000, Peter Maydell wrote:
> 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.

So if this is a host OS package bug we punt to OS vendor to fix,
and just apply workaround in our CI ?  eg

$ git diff
diff --git a/.travis.yml b/.travis.yml
index c3c8048842..6da4c9f640 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -218,6 +218,7 @@ jobs:
         - TEST_CMD="make check check-tcg V=1"
         - CONFIG="--disable-containers 
--target-list=${MAIN_SOFTMMU_TARGETS},s390x-linux-user"
         - UNRELIABLE=true
+        - DFLTCC=0
       script:
         - BUILD_RC=0 && make -j${JOBS} || BUILD_RC=$?
         - |



Regards,
Daniel
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