Re: [PULL 26/34] migration/multifd: Join the TLS thread

[Michael Tokarev]

14.02.2024 16:27, Fabiano Rosas :
> Michael Tokarev <mjt@tls.msk.ru> writes:
..>>> This change, which is suggested for -stable, while simple by its own, 
seems
> > > to depend on the previous changes in this series, which are not for -stable.
> > > In particular, whole "Finally recycle all the threads" loop in 
> > > multifd_send_terminate_threads()
> > > (to which the join is being added by this change) is moved from elsewhere by
> > > 12808db3b8 "migration/multifd: Cleanup multifd_save_cleanup()" (patch 24 in
> > > this same series).
> > We can probably add the missing join right into the previous location of this
> > loop (before 12808db3b8).  I did this in the attached variant for 8.2, is
> > this correct?

I forgot to attach the patch.  It just moves the join from 
multifd_send_terminate_threads()
back to multifd_save_cleanup.  Attached now.

> It should work. This was originally developed without the rest of the
> changes on this PR.
>
> > And this does not pass even the basic tests, so it's not that simple :)
>
> Do you have a log of what failed?

Re-running it again...  I haven't even tried to push it somewhere for CI to run,
I run local `ninja test', which painted some migration tests in red.  Here:

202/844 qemu:qtest+qtest-aarch64 / qtest-aarch64/migration-test   ERROR   
70.26s   killed by signal 6 SIGABRT
330/844 qemu:qtest+qtest-i386 / qtest-i386/migration-test         ERROR   
85.33s   killed by signal 6 SIGABRT
454/844 qemu:qtest+qtest-x86_64 / qtest-x86_64/migration-test     ERROR  
101.02s   killed by signal 6 SIGABRT

Unfortunately I don't see anything interesting in the log:

# starting QEMU: exec ./qemu-system-x86_64 -qtest unix:/tmp/qtest-463614.sock -qtest-log /dev/null -chardev socket,path=/tmp/qtest-463614.qmp,id=char0 
-mon chardev=char0,mode=control -display none -audio none -accel kvm -accel tcg -machine pc-q35-8.2, -name target,debug-threads=on -m 150M -serial 
file:/tmp/migration-test-SPJTI2/dest_serial -incoming defer -drive if=none,id=d0,file=/tmp/migration-test-SPJTI2/bootsect,format=raw -device 
ide-hd,drive=d0,secs=1,cyls=1,heads=1    2>/dev/null -accel qtest
----------------------------------- stderr -----------------------------------
../../build/qemu/8.2/tests/qtest/libqtest.c:204: kill_qemu() detected QEMU 
death from signal 6 (Aborted)
(test program exited with status code -6)

Without the attached patch it works.

> Anyway, I could prepare a backport on top of 8.2 for you.

Well, that would definitely be helpful, if you think it's worth to
provide backports for 8.2 for these.   As my attempt apparently isn't
very successful :)

> > The following patch (27/34) is more questionable than this one.

Thank you!

/mjt

0001-migration-multifd-Join-the-TLS-thread.patch
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