[Rd] Very hard to reproduce bug (?) in R-devel

[Uwe Ligges]

On 05.04.2017 23:54, peter dalgaard wrote:
>
>> On 05 Apr 2017, at 20:40 , Winston Chang <winstonchang1 at gmail.com> wrote:
>>
>> I think there's a good chance that this is due to a bug in R. I have
>> been trying to track down the cause of the problem but haven't been
>> able find it.
>>
>> -Winston
>
> Apologies in advance if this is just stating the obvious, but let me try and put some general ideas  on the table.
>
> - is anything non-deterministic involved? (Doesn't sound so, but...)
> - could it be something with the bytecompiler?

Also my suspicion, can you try without having JIT enabled?

Best,
Uwe Ligges



> - can you get something (_anything_) to trigger the bug (in any variant) when running R under gdb? I'm thinking gctorture() etc.
> - it is odd that you cannot immediately get the same behaviour with R -d gdb or valgrind. Are you sure you are actually running the same script in the same way?
> - if you can get a hold of something inside gdb, then there should be some potential for backtracking using hardware watchpoints and such. As in: This memory location doesn't contain the value I expected; what changed it?
>
> -pd
>
>