Fabiano Rosas <faro...@suse.de> writes: > Peter Xu <pet...@redhat.com> writes: > >> On Thu, Sep 12, 2024 at 09:13:16AM +0100, Peter Maydell wrote: >>> On Wed, 11 Sept 2024 at 22:26, Fabiano Rosas <faro...@suse.de> wrote: >>> > I don't think we're discussing total CI time at this point, so the math >>> > doesn't really add up. We're not looking into making the CI finish >>> > faster. We're looking into making migration-test finish faster. That >>> > would reduce timeouts in CI, speed-up make check and reduce the chance >>> > of random race conditions* affecting other people/staging runs. >>> >>> Right. The reason migration-test appears on my radar is because >>> it is very frequently the thing that shows up as "this sometimes >>> just fails or just times out and if you hit retry it goes away >>> again". That might not be migration-test's fault specifically, >>> because those retries tend to be certain CI configs (s390, >>> the i686-tci one), and I have some theories about what might be >>> causing it (e.g. build system runs 4 migration-tests in parallel, >>> which means 8 QEMU processes which is too many for the number >>> of host CPUs). But right now I look at CI job failures and my reaction >>> is "oh, it's the migration-test failing yet again" :-( >>> >>> For some examples from this week: >>> >>> https://gitlab.com/qemu-project/qemu/-/jobs/7802183144 >>> https://gitlab.com/qemu-project/qemu/-/jobs/7799842373 <--------[1] >>> https://gitlab.com/qemu-project/qemu/-/jobs/7786579152 <--------[2] >>> https://gitlab.com/qemu-project/qemu/-/jobs/7786579155 >> >> Ah right, the TIMEOUT is unfortunate, especially if tests can be run in >> parallel. It indeed sounds like no good way to finally solve.. I don't >> also see how speeding up / reducing tests in migration test would help, as >> that's (from some degree..) is the same as tuning the timeout value bigger. >> When the tests are less it'll fit into 480s window, but maybe it's too >> quick now we wonder whether we should shrink it to e.g. 90s, but then it >> can timeout again when on a busy host with less capability of concurrency. >> >> But indeed there're two ERRORs ([1,2] above).. I collected some more info >> here before the log expires: >> >> =================================8<================================ >> >> *** /i386/migration/multifd/tcp/plain/cancel, qtest-i386 on s390 host >> >> https://gitlab.com/qemu-project/qemu/-/jobs/7799842373 >> >> 101/953 qemu:qtest+qtest-i386 / qtest-i386/migration-test >> ERROR 144.32s killed by signal 6 SIGABRT >>>>> QTEST_QEMU_STORAGE_DAEMON_BINARY=./storage-daemon/qemu-storage-daemon >>>>> G_TEST_DBUS_DAEMON=/home/gitlab-runner/builds/zEr9wY_L/0/qemu-project/qemu/tests/dbus-vmstate-daemon.sh >>>>> >>>>> PYTHON=/home/gitlab-runner/builds/zEr9wY_L/0/qemu-project/qemu/build/pyvenv/bin/python3 >>>>> QTEST_QEMU_IMG=./qemu-img MALLOC_PERTURB_=144 >>>>> QTEST_QEMU_BINARY=./qemu-system-i386 >>>>> /home/gitlab-runner/builds/zEr9wY_L/0/qemu-project/qemu/build/tests/qtest/migration-test >>>>> --tap -k >> ――――――――――――――――――――――――――――――――――――― ✀ >> ――――――――――――――――――――――――――――――――――――― >> stderr: >> warning: fd: migration to a file is deprecated. Use file: instead. >> warning: fd: migration to a file is deprecated. Use file: instead. >> ../tests/qtest/libqtest.c:205: kill_qemu() detected QEMU death from signal >> 11 (Segmentation fault) (core dumped) >> (test program exited with status code -6) >> TAP parsing error: Too few tests run (expected 53, got 39) >> ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― >> >> # Start of plain tests >> # Running /i386/migration/multifd/tcp/plain/cancel >> # Using machine type: pc-i440fx-9.2 >> # starting QEMU: exec ./qemu-system-i386 -qtest unix:/tmp/qtest-3273509.sock >> -qtest-log /dev/null -chardev socket,path=/tmp/qtest-3273509.qmp,id=char0 >> -mon chardev=char0,mode=control -display none -audio none -accel kvm -accel >> tcg -machine pc-i440fx-9.2, -name source,debug-threads=on -m 150M -serial >> file:/tmp/migration-test-4112T2/src_serial -drive >> if=none,id=d0,file=/tmp/migration-test-4112T2/bootsect,format=raw -device >> ide-hd,drive=d0,secs=1,cyls=1,heads=1 2>/dev/null -accel qtest >> # starting QEMU: exec ./qemu-system-i386 -qtest unix:/tmp/qtest-3273509.sock >> -qtest-log /dev/null -chardev socket,path=/tmp/qtest-3273509.qmp,id=char0 >> -mon chardev=char0,mode=control -display none -audio none -accel kvm -accel >> tcg -machine pc-i440fx-9.2, -name target,debug-threads=on -m 150M -serial >> file:/tmp/migration-test-4112T2/dest_serial -incoming defer -drive >> if=none,id=d0,file=/tmp/migration-test-4112T2/bootsect,format=raw -device >> ide-hd,drive=d0,secs=1,cyls=1,heads=1 2>/dev/null -accel qtest >> ----------------------------------- stderr >> ----------------------------------- >> warning: fd: migration to a file is deprecated. Use file: instead. >> warning: fd: migration to a file is deprecated. Use file: instead. >> ../tests/qtest/libqtest.c:205: kill_qemu() detected QEMU death from signal >> 11 (Segmentation fault) (core dumped) >> >> *** /ppc64/migration/multifd/tcp/plain/cancel, qtest-ppc64 on i686 host >> >> https://gitlab.com/qemu-project/qemu/-/jobs/7786579152 >> >> 174/315 qemu:qtest+qtest-ppc64 / qtest-ppc64/migration-test >> ERROR 381.00s killed by signal 6 SIGABRT >>>>> PYTHON=/builds/qemu-project/qemu/build/pyvenv/bin/python3 >>>>> QTEST_QEMU_IMG=./qemu-img >>>>> G_TEST_DBUS_DAEMON=/builds/qemu-project/qemu/tests/dbus-vmstate-daemon.sh >>>>> QTEST_QEMU_BINARY=./qemu-system-ppc64 MALLOC_PERTURB_=178 >>>>> QTEST_QEMU_STORAGE_DAEMON_BINARY=./storage-daemon/qemu-storage-daemon >>>>> /builds/qemu-project/qemu/build/tests/qtest/migration-test --tap -k >> ――――――――――――――――――――――――――――――――――――― ✀ >> ――――――――――――――――――――――――――――――――――――― >> stderr: >> qemu-system-ppc64: Cannot read from TLS channel: The TLS connection was >> non-properly terminated. >> warning: fd: migration to a file is deprecated. Use file: instead. >> warning: fd: migration to a file is deprecated. Use file: instead. >> ../tests/qtest/libqtest.c:205: kill_qemu() detected QEMU death from signal >> 11 (Segmentation fault) (core dumped) >> (test program exited with status code -6) >> TAP parsing error: Too few tests run (expected 61, got 47) >> ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― >> >> # Start of plain tests >> # Running /ppc64/migration/multifd/tcp/plain/cancel >> # Using machine type: pseries-9.2 >> # starting QEMU: exec ./qemu-system-ppc64 -qtest unix:/tmp/qtest-40766.sock >> -qtest-log /dev/null -chardev socket,path=/tmp/qtest-40766.qmp,id=char0 -mon >> chardev=char0,mode=control -display none -audio none -accel kvm -accel tcg >> -machine pseries-9.2,vsmt=8 -name source,debug-threads=on -m 256M -serial >> file:/tmp/migration-test-H0Z1T2/src_serial -nodefaults -machine >> cap-cfpc=broken,cap-sbbc=broken,cap-ibs=broken,cap-ccf-assist=off, -bios >> /tmp/migration-test-H0Z1T2/bootsect 2>/dev/null -accel qtest >> # starting QEMU: exec ./qemu-system-ppc64 -qtest unix:/tmp/qtest-40766.sock >> -qtest-log /dev/null -chardev socket,path=/tmp/qtest-40766.qmp,id=char0 -mon >> chardev=char0,mode=control -display none -audio none -accel kvm -accel tcg >> -machine pseries-9.2,vsmt=8 -name target,debug-threads=on -m 256M -serial >> file:/tmp/migration-test-H0Z1T2/dest_serial -incoming defer -nodefaults >> -machine cap-cfpc=broken,cap-sbbc=broken,cap-ibs=broken,cap-ccf-assist=off, >> -bios /tmp/migration-test-H0Z1T2/bootsect 2>/dev/null -accel qtest >> ----------------------------------- stderr >> ----------------------------------- >> qemu-system-ppc64: Cannot read from TLS channel: The TLS connection was >> non-properly terminated. >> warning: fd: migration to a file is deprecated. Use file: instead. >> warning: fd: migration to a file is deprecated. Use file: instead. >> ../tests/qtest/libqtest.c:205: kill_qemu() detected QEMU death from signal >> 11 (Segmentation fault) (core dumped) >> >> (test program exited with status code -6) >> =================================8<================================ >> >> So.. it's the same test (multifd/tcp/plain/cancel) that is failing on >> different host / arch being tested. What is more weird is the two failures >> are different, the 2nd failure throw out a TLS error even though the test >> doesn't yet have tls involved. > > I think that's just a parallel test being cancelled prematurely, either > due to the crash or due to the timeout. > >> >> Fabiano, is this the issue you're looking at? > > Yes. I can reproduce locally by running 2 processes in parallel: 1 loop > with make -j$(nproc) check and another loop with tcp/plain/cancel. It > takes ~1h to hit. I've seen crashes with ppc64, s390 and > aarch64. >
Ok, the issue is that after commit 5ef7e26bdb ("migration/multifd: solve zero page causing multiple page faults"), the multifd code started using the rb->receivedmap bitmap, which belongs to the ram code and is initialized and *freed* from the ram SaveVMHandlers. process_incoming_migration_co() ... qemu_loadvm_state() multifd_nocomp_recv() qemu_loadvm_state_cleanup() ramblock_recv_bitmap_set_offset() rb->receivedmap = NULL set_bit_atomic(..., rb->receivedmap) ... migration_incoming_state_destroy() multifd_recv_cleanup() multifd_recv_terminate_threads(NULL) Multifd threads are live until migration_incoming_state_destroy(), which is called some time later. >> Peter, do you think it'll be helpful if we temporarily mark this test as >> "slow" too so it's not run in CI (so we still run it ourselves when prepare >> migration PR, with the hope that it can reproduce)? >> >> Thanks,