Re: [Qemu-devel] Confusion regarding temporaries with branch conditional

[Richard Henderson]

On 11/30/2016 08:55 AM, Alex Bennée wrote:
> 
> Nikunj A Dadhania <address@hidden> writes:
> 
>> Hi,
>>
>> I was writing one instruction and hit following issue:
>>
>> [snip]/qemu/tcg/tcg.c:2039: tcg fatal error
>> qemu-ppc64le: [snip]/qemu/translate-all.c:175: tb_lock: Assertion 
>> `!have_tb_lock' failed.
>> Segmentation fault (core dumped)
> 
> This is confusing because something is trying to take the tb_lock while
> you are in code generation. tb_lock is held for code generation to
> ensure serialisation of generation.

Yes, I've seen this myself.  I never got around to reporting the "problem"
properly.  It's a confusing side effect of a SIGSEGV arriving during tcg code
generation.  The signal handler longjmps back with unexpected locks held.

Probably we should simply crash earlier and less confusingly.


r~