On Fri, Jun 29, 2018 at 10:25:03 +0300, Pavel Dovgalyuk wrote:
> This patch breaks record/replay.
>
> I run execution recording of the WindowsXP machine with the following script:
>
> ./bin/qemu-system-i386 -d in_asm,exec -D xp_save.log -global
> apic-common.vapic=off \
> -icount shift=7,rr=record,rrfile=xp0.replay \
> -drive file=./images/xp_sp2.qcow2,if=none,id=img-direct,snapshot \
> -drive driver=blkreplay,if=none,image=img-direct,id=img-replay \
> -device ide-hd,drive=img-replay -net none -m 512M
>
> QEMU fails at some moment. Here are the contents of the log:
>
> ----------------
> IN:
> 0x806ee2d0: 33 c0 xorl %eax, %eax
> 0x806ee2d2: 8a c1 movb %cl, %al
> 0x806ee2d4: 33 c9 xorl %ecx, %ecx
> 0x806ee2d6: 8a 88 58 e2 6e 80 movb -0x7f911da8(%eax), %cl
> 0x806ee2dc: 89 0d 80 00 fe ff movl %ecx, 0xfffe0080
> 0x806ee2e2: a1 80 00 fe ff movl 0xfffe0080, %eax
> 0x806ee2e7: c3 retl
>
> Trace 0: 0x7fdc103b16a0 [00000000/806ee2d0/0x4000b0]
> qemu: fatal: cpu_io_recompile: could not find TB for pc=0x7fec24fde2de
Thanks for reporting.
>From code inspection I can see how this could happen: we're calling
tcg_tb_remove for a TB that we did not just generate--we got an
existing one instead. Note that CF_NOCACHE is not part of
the CF_HASH mask, so this might explain why the problem only
occurs for r/r.
Can you reproduce this with any other guest? If not, I'd be
happy to use your windows qcow2 file if you could share it
with me off-list.
Thanks,
Emilio
