Re: [Qemu-devel] [PATCH v2] target-sh4: add atomic tas

[Laurent Vivier]

Le 04/11/2016 à 10:43, John Paul Adrian Glaubitz a écrit :
> On 11/04/2016 10:23 AM, John Paul Adrian Glaubitz wrote:
>> On 11/03/2016 05:21 PM, Laurent Vivier wrote:
>>> It should,:the problem was reported by Adrian (cc:) while compiling ghc
>>> in qemu-sh4, but I have just tested the functionality with the softmmu
>>> version, not the atomicity.
>>>
>>> Adrian, could you test this patch?
>>
>> Will absolutely do that. Awesome to see progress here :).
> 
> Ok, I couldn't wait. It doesn't help with the GHC issue, unfortunately:
> 
> address@hidden:~/ghc-7.8.4/utils/ghc-pwd# ghc Main.hs
> [1 of 1] Compiling Main             ( Main.hs, Main.o )
> qemu-sh4-static: /home/glaubitz/upstream/qemu/translate-all.c:175: tb_lock: 
> Assertion `!have_tb_lock' failed.
> qemu-sh4-static: /home/glaubitz/upstream/qemu/translate-all.c:175: tb_lock: 
> Assertion `!have_tb_lock' failed.
> Segmentation fault
> address@hidden:~/ghc-7.8.4/utils/ghc-pwd#
> 
> I've also seen it lock up and strace showing it hanging in a futex lock.

I think it's more likely a linux-user bug than a target-sh4 bug.

As you report in a mail to me in February, "do_futex()" must be
protected against parallel execution for some futex commands.

Thanks,
Laurent