Re: [PATCH v3 06/10] migration-test: Add COLO migration unit test

[Lukas Straub <lukasstraub2@web.de>]

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On Tue, 27 Jan 2026 15:49:31 -0500
Peter Xu <peterx@redhat.com> wrote:

> On Sun, Jan 25, 2026 at 09:40:11PM +0100, Lukas Straub wrote:
> > +void migration_test_add_colo(MigrationTestEnv *env)
> > +{
> > +    if (!env->has_kvm) {
> > +        g_test_skip("COLO requires KVM accelerator");
> > +        return;
> > +    }  
> 
> I'm OK if you want to explicitly bypass others, but could you explanation
> why?
> 
> Thanks,
> 

It used to hang with TCG. Now it crashes, since
migration_bitmap_sync_precopy assumes bql is held. Something for later.

#6  0x00007ffff7471517 in __assert_fail
    (assertion=assertion@entry=0x555555f17aee "bql_locked() != locked", file=file@entry=0x555555f17ab0 "../system/cpus.c", line=line@entry=535, function=function@entry=0x55555609bfd0 <__PRETTY_FUNCTION__.9> "bql_update_status") at ./assert/assert.c:105
#7  0x0000555555b09f1e in bql_update_status (locked=locked@entry=false) at ../system/cpus.c:535
#8  0x0000555555ec60e7 in qemu_mutex_pre_unlock (mutex=0x555557166700 <bql>, file=0x555555efe1dc "../cpu-common.c", line=164) at ../util/qemu-thread-common.h:57
#9  qemu_mutex_pre_unlock (line=164, file=0x555555efe1dc "../cpu-common.c", mutex=0x555557166700 <bql>) at ../util/qemu-thread-common.h:48
#10 qemu_cond_wait_impl (cond=0x5555571442c0 <qemu_work_cond>, mutex=0x555557166700 <bql>, file=0x555555efe1dc "../cpu-common.c", line=164) at ../util/qemu-thread-posix.c:224
#11 0x000055555589e6c8 in do_run_on_cpu (cpu=<optimized out>, func=<optimized out>, data=..., mutex=0x555557166700 <bql>) at ../cpu-common.c:164
#12 0x0000555555b17a06 in memory_global_after_dirty_log_sync () at ../system/memory.c:2938
#13 0x0000555555b55b47 in migration_bitmap_sync (rs=0x7fffe8001340, last_stage=last_stage@entry=true) at ../migration/ram.c:1157
#14 0x0000555555b56721 in migration_bitmap_sync_precopy (last_stage=last_stage@entry=true) at ../migration/ram.c:1195
#15 0x0000555555b59f8a in ram_save_complete (f=0x5555575db620, opaque=<optimized out>) at ../migration/ram.c:3381
#16 0x0000555555b5e4f5 in qemu_savevm_complete (se=se@entry=0x5555574c0d80, f=f@entry=0x5555575db620) at ../migration/savevm.c:1521
#17 0x0000555555b60437 in qemu_savevm_state_complete_precopy_iterable (f=f@entry=0x5555575db620, in_postcopy=in_postcopy@entry=false) at ../migration/savevm.c:1627
#18 0x0000555555b60a4f in qemu_savevm_state_complete_precopy (iterable_only=true, f=0x5555575db620) at ../migration/savevm.c:1719
#19 qemu_savevm_live_state (f=0x5555575db620) at ../migration/savevm.c:1855
#20 0x0000555555b65ed9 in colo_do_checkpoint_transaction (fb=<optimized out>, bioc=<optimized out>, s=0x5555574c0070) at ../migration/colo.c:474
#21 colo_process_checkpoint (s=0x5555574c0070) at ../migration/colo.c:592
#22 migrate_start_colo_process (s=0x5555574c0070) at ../migration/colo.c:655
#23 0x0000555555b4971e in migration_iteration_finish (s=0x5555574c0070) at ../migration/migration.c:3297
#24 migration_thread (opaque=opaque@entry=0x5555574c0070) at ../migration/migration.c:3584
#25 0x0000555555ec58c0 in qemu_thread_start (args=0x5555576583e0) at ../util/qemu-thread-posix.c:393
#26 0x00007ffff74d2aa4 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:447
#27 0x00007ffff755fc6c in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

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