Re: [PATCH for 7.2-rc3 v1 0/2] virtio fixes

["Alex Bennée" <alex.bennee@linaro.org>]

"Michael S. Tsirkin" <mst@redhat.com> writes:

> On Thu, Nov 24, 2022 at 09:21:15AM +0000, Alex Bennée wrote:
>> 
>> "Michael S. Tsirkin" <mst@redhat.com> writes:
>> 
>> > On Wed, Nov 23, 2022 at 04:03:49PM +0000, Alex Bennée wrote:
>> >> 
>> >> "Michael S. Tsirkin" <mst@redhat.com> writes:
>> >> 
>> >> > On Wed, Nov 23, 2022 at 03:21:32PM +0000, Alex Bennée wrote:
>> >> >> Hi,
>> >> >> 
>> >> >> This hopefully fixes the problems with VirtIO migration caused by the
>> >> >> previous refactoring of virtio_device_started(). That introduced a
>> >> >> different order of checking which didn't give the VM state primacy but
>> >> >> wasn't noticed as we don't properly exercise VirtIO device migration
>> >> >> and caused issues when dev->started wasn't checked in the core code.
>> >> >> The introduction of virtio_device_should_start() split the overloaded
>> >> >> function up but the broken order still remained. The series finally
>> >> >> fixes that by restoring the original semantics but with the cleaned up
>> >> >> functions.
>> >> >> 
>> >> >> I've added more documentation to the various structures involved as
>> >> >> well as the functions. There is still some inconsistencies in the
>> >> >> VirtIO code between different devices but I think that can be looked
>> >> >> at over the 8.0 cycle.
>> >> >
>> >> >
>> >> > Thanks a lot! Did you try this with gitlab CI? A patch similar to your
>> >> > 2/2 broke it previously ...
>> >> 
>> >> Looking into it now - so far hasn't broken locally but I guess there is
>> >> something different about the CI.
>> >
>> >
>> > yes - pls push to gitlab, create pipeline e.g. with QEMU_CI set to 2
>> >
>> > Or with QEMU_CI set to 1 and then run fedora container and then
>> > clang-system manually.
>> 
>> I'm having trouble re-creating the failures in CI locally on my boxen. I
>> have triggered a bug on s390 but that looks like a pre-existing problem
>> with VRING_SET_ENDIAN being triggered for the vhost-user-gpio tests. I
>> think that is a limitation of the test harness.
>> 
>> Will keep looking.
>
> Why not just trigger it on gitlab CI - it's very repeatable there?

I can repeat a problem locally on Debian Bullseye and Ubuntu 22.04 with clang and leak sanitizer:

  # QEMU configure log Thu 24 Nov 16:02:56 GMT 2022
  # Configured with: '../../configure' '--cc=clang' '--cxx=clang++' '--enable-sanitizers' '--target-list=arm-softmmu,aarch64-softmmu,i386-softmmu,x86_64-softmmu,ppc64-softmmu'#

And the command:

  env QTEST_QEMU_BINARY=./qemu-system-arm QTEST_QEMU_STORAGE_DAEMON_BINARY=./storage-daemon/qemu-storage-daemon QTEST_QEMU_IMG=./qemu-img MALLOC_PERTURB_=178 G_TEST_DBUS_DAEMON=/home/alex.bennee/lsrc/qemu.git/tests/dbus-vmstate-daemon.sh ./tests/qtest/qos-test -p /arm/virt/virtio-mmio/virtio-bus/vhost-user-gpio-device/vhost-user-gpio/vhost-user-gpio-tests/read-guest-mem/memfile/subprocess

Gives the following failure, while a leak may not be that exciting it
does point to a potential corruption issue. Unfortunately I don't get a
decent backtrace from the tool:

  # random seed: R02S071fe8d68317a8b01e5e7fadbf1ac60a
  # starting QEMU: exec ./qemu-system-arm -qtest unix:/tmp/qtest-1024352.sock -qtest-log /dev/null -chardev socket,path=/tmp/qtest-1024352.qmp,id=char0 -mon chardev=char0,mode=control -display none -machine none -accel qtest
  ==1024354==WARNING: ASan doesn't fully support makecontext/swapcontext functions and may produce false positives in some cases!
  # Start of arm tests
  # Start of virt tests
  # Start of virtio-mmio tests
  # Start of virtio-bus tests
  # Start of vhost-user-gpio-device tests
  # Start of vhost-user-gpio tests
  # Start of vhost-user-gpio-tests tests
  # Start of read-guest-mem tests
  # Start of memfile tests
  # starting QEMU: exec ./qemu-system-arm -qtest unix:/tmp/qtest-1024352.sock -qtest-log /dev/null -chardev socket,path=/tmp/qtest-1024352.qmp,id=char0 -mon chardev=char0,mode=control -display none -M virt  -device vhost-user-gpio-device,id=gpio0,chardev=chr-vhost-user-test -m 256 -object memory-backend-memfd,id=mem,size=256M, -numa node,memdev=mem -chardev socket,id=chr-vhost-user-test,path=/tmp/vhost-test-8DD2V1/vhost-user-test.sock -accel qtest
  # GLib-DEBUG: setenv()/putenv() are not thread-safe and should not be used after threads are created
  ==1024371==WARNING: ASan doesn't fully support makecontext/swapcontext functions and may produce false positives in some cases!
  # set_protocol_features: 0x200
  # set_owner: start of session
  # vhost-user: un-handled message: 14
  # vhost-user: un-handled message: 14
  # set_vring_num: 0/1024
  qemu-system-arm: Failed to set msg fds.
  qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
  qemu-system-arm: Failed to set msg fds.
  qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
  qemu-system-arm: Failed to set msg fds.
  qemu-system-arm: vhost_set_vring_call failed: Invalid argument (22)
  qemu-system-arm: Failed to set msg fds.
  qemu-system-arm: vhost_set_vring_call failed: Invalid argument (22)
  ok 1 /arm/virt/virtio-mmio/virtio-bus/vhost-user-gpio-device/vhost-user-gpio/vhost-user-gpio-tests/read-guest-mem/memfile/subprocess # SKIP No memory at address 0x0
  # End of memfile tests
  # End of read-guest-mem tests
  # End of vhost-user-gpio-tests tests
  # End of vhost-user-gpio tests
  # End of vhost-user-gpio-device tests
  # End of virtio-bus tests
  # End of virtio-mmio tests
  # End of virt tests
  # End of arm tests
  1..1

  =================================================================
  ==1024371==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 240 byte(s) in 1 object(s) allocated from:
      #0 0x561d9a5d7a18 in __interceptor_calloc (/home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/qemu-system-arm+0x1d1fa18) (BuildId: 0bdc7c2ada2277089db16d57f17c314e9e53e41c)
      #1 0x7f46ee656c40 in g_malloc0 (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x5ec40) (BuildId: 0ab0b740e34eeb0c84656ba53737f4c440dfbed4)
      #2 0x561d9bf7875b in virtio_device_realize /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../hw/virtio/virtio.c:4175:9
      #3 0x561d9c321bf4 in device_set_realized /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../hw/core/qdev.c:566:13
      #4 0x561d9c33dda8 in property_set_bool /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../qom/object.c:2285:5
      #5 0x561d9c338fb3 in object_property_set /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../qom/object.c:1420:5
      #6 0x561d9c344c7c in object_property_set_qobject /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../qom/qom-qobject.c:28:10
      #7 0x561d9b367954 in qdev_device_add /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../softmmu/qdev-monitor.c:733:11
      #8 0x561d9b36f832 in qemu_create_cli_devices /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../softmmu/vl.c:2536:5
      #9 0x561d9b36f832 in qmp_x_exit_preconfig /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../softmmu/vl.c:2604:5
      #10 0x561d9b37613f in qemu_init /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../softmmu/vl.c:3601:9
      #11 0x561d9a6125a5 in main /home/alex.bennee/lsrc/qemu.git/builds/all.clang-sanitizers/../../softmmu/main.c:47:5

  SUMMARY: AddressSanitizer: 240 byte(s) leaked in 1 allocation(s).
  ../../tests/qtest/libqtest.c:179: kill_qemu() tried to terminate QEMU process but encountered exit status 1 (expected 0)
  fish: Job 1, 'env QTEST_QEMU_BINARY=./qemu-sy…' terminated by signal SIGABRT (Abort)
  🕙22:26:18 alex.bennee@hackbox2:qemu.git/builds/all.clang-sanitizers  on  for-7.2/virtio-fixes [$?] [⚡ IOT]
  ✗



>> >
>> >> >
>> >> >> Alex Bennée (2):
>> >> >>   include/hw: attempt to document VirtIO feature variables
>> >> >>   include/hw: VM state takes precedence in virtio_device_should_start
>> >> >> 
>> >> >>  include/hw/virtio/vhost.h  | 25 +++++++++++++++++++---
>> >> >>  include/hw/virtio/virtio.h | 43 ++++++++++++++++++++++++++++++++------
>> >> >>  2 files changed, 59 insertions(+), 9 deletions(-)
>> >> >> 
>> >> >> -- 
>> >> >> 2.34.1
>> >> 
>> >> 
>> >> -- 
>> >> Alex Bennée
>> 
>> 
>> -- 
>> Alex Bennée


-- 
Alex Bennée