Re: [PULL 00/21] Migration 20230530 patches

[Daniel P . Berrangé]

On Thu, Jun 01, 2023 at 09:27:09AM +0100, Daniel P. Berrangé wrote:
> On Wed, May 31, 2023 at 11:03:23PM +0200, Juan Quintela wrote:
> > Richard Henderson <richard.henderson@linaro.org> wrote:
> > > On 5/30/23 11:25, Juan Quintela wrote:
> > >> The following changes since commit 
> > >> aa9bbd865502ed517624ab6fe7d4b5d89ca95e43:
> > >>    Merge tag 'pull-ppc-20230528' of https://gitlab.com/danielhb/qemu
> > >> into staging (2023-05-29 14:31:52 -0700)
> > >> are available in the Git repository at:
> > >>    https://gitlab.com/juan.quintela/qemu.git
> > >> tags/migration-20230530-pull-request
> > >> for you to fetch changes up to
> > >> c63c544005e6b1375a9c038f0e0fb8dfb8b249f4:
> > >>    migration/rdma: Check sooner if we are in postcopy for
> > >> save_page() (2023-05-30 19:23:50 +0200)
> > >> ----------------------------------------------------------------
> > 
> > Added Markus and Daniel.
> > 
> > >> Migration 20230530 Pull request (take 2)
> > >> Hi
> > >> Resend last PULL request, this time it compiles when CONFIG_RDMA is
> > >> not configured in.
> > >> [take 1]
> > >> On this PULL request:
> > >> - Set vmstate migration failure right (vladimir)
> > >> - Migration QEMUFileHook removal (juan)
> > >> - Migration Atomic counters (juan)
> > >> Please apply.
> > >> ----------------------------------------------------------------
> > >> Juan Quintela (16):
> > >>    migration: Don't abuse qemu_file transferred for RDMA
> > >>    migration/RDMA: It is accounting for zero/normal pages in two places
> > >>    migration/rdma: Remove QEMUFile parameter when not used
> > >>    migration/rdma: Don't use imaginary transfers
> > >>    migration: Remove unused qemu_file_credit_transfer()
> > >>    migration/rdma: Simplify the function that saves a page
> > >>    migration: Create migrate_rdma()
> > >>    migration/rdma: Unfold ram_control_before_iterate()
> > >>    migration/rdma: Unfold ram_control_after_iterate()
> > >>    migration/rdma: Remove all uses of RAM_CONTROL_HOOK
> > >>    migration/rdma: Unfold hook_ram_load()
> > >>    migration/rdma: Create rdma_control_save_page()
> > >>    qemu-file: Remove QEMUFileHooks
> > >>    migration/rdma: Move rdma constants from qemu-file.h to rdma.h
> > >>    migration/rdma: Remove qemu_ prefix from exported functions
> > >>    migration/rdma: Check sooner if we are in postcopy for save_page()
> > >> Vladimir Sementsov-Ogievskiy (5):
> > >>    runstate: add runstate_get()
> > >>    migration: never fail in global_state_store()
> > >>    runstate: drop unused runstate_store()
> > >>    migration: switch from .vm_was_running to .vm_old_state
> > >>    migration: restore vmstate on migration failure
> > >
> > > Appears to introduce multiple avocado failures:
> > >
> > > https://gitlab.com/qemu-project/qemu/-/jobs/4378066518#L286
> > >
> > > Test summary:
> > > tests/avocado/migration.py:X86_64.test_migration_with_exec: ERROR
> > > tests/avocado/migration.py:X86_64.test_migration_with_tcp_localhost: ERROR
> > > tests/avocado/migration.py:X86_64.test_migration_with_unix: ERROR
> > > make: *** [/builds/qemu-project/qemu/tests/Makefile.include:142: 
> > > check-avocado] Error 1
> > >
> > > https://gitlab.com/qemu-project/qemu/-/jobs/4378066523#L387
> > >
> > > Test summary:
> > > tests/avocado/migration.py:X86_64.test_migration_with_tcp_localhost: ERROR
> > > tests/avocado/migration.py:X86_64.test_migration_with_unix: ERROR
> > > make: *** [/builds/qemu-project/qemu/tests/Makefile.include:142: 
> > > check-avocado] Error 1
> > >
> > > Also fails QTEST_QEMU_BINARY=./qemu-system-aarch64 
> > > ./tests/qtest/migration-test
> > >
> > > ../src/migration/rdma.c:408:QIO_CHANNEL_RDMA: Object 0xaaaaf7bba680 is
> > > not an instance of type qio-channel-rdma
> > 
> > I am looking at the other errors, but this one is weird.  It is failing
> > here:
> > 
> > #define TYPE_QIO_CHANNEL_RDMA "qio-channel-rdma"
> > OBJECT_DECLARE_SIMPLE_TYPE(QIOChannelRDMA, QIO_CHANNEL_RDMA)
> > 
> > In the OBJECT line.
> > 
> > I have no clue what problem are we having here with the object system to
> > decide at declaration time that a variable is not of the type that we
> > are declaring.
> > 
> > I am missing something obvious here?
> 
> I expect somewhere in the code has either corrupted memory, or is
> using free'd memory. Either way you'll need to get a stack trace
> to debug this kind of thing

I've replied to the patches pointing out 4 places where the code
casts to QIOChannelRDMA, without first checking that this is an
RDMA migration, which look likely to be the cause of this.


With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|