This is a race that can happen when migrating TCG guests under load. It was introduced by the change to run vCPUs outside the big QEMU lock.
Paolo Bonzini (4): memory: remove memory_region_test_and_clear_dirty memory: hide memory_region_sync_dirty_bitmap behind DirtyBitmapSnapshot memory: introduce memory_global_after_dirty_log_sync memory: unify loops to sync dirty log bitmap exec.c | 31 ++++++++++++++++++ hw/display/cg3.c | 1 - hw/display/exynos4210_fimd.c | 1 - hw/display/framebuffer.c | 1 - hw/display/g364fb.c | 1 - hw/display/sm501.c | 1 - hw/display/tcx.c | 2 -- hw/display/vga.c | 6 ---- include/exec/memory.h | 47 +++++++++------------------ memory.c | 76 +++++++++++++++++--------------------------- migration/ram.c | 1 + 11 files changed, 76 insertions(+), 92 deletions(-) -- 2.14.3