Fabiano Rosas <faro...@suse.de> writes: > Peter Xu <pet...@redhat.com> writes: > >> On Thu, Sep 12, 2024 at 07:52:48PM -0300, Fabiano Rosas wrote: >>> 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. >> >> Thanks for the debugging. Hmm I would expect loadvm should wait until all >> ram is received somehow.. > > Looks like a similar issue as when we didn't have the multifd_send sync > working correctly and ram code would run and do cleanup.
Btw, this is hard to debug, but I bet what's happening is that the ram_load code itself is exiting due to qemufile error. So there wouldn't be a way to make it wait for multifd.
