Re: Non-reproducible AIO failure

Hi,

On 2025-06-10 21:09:18 +0300, Konstantin Knizhnik wrote:
>
> On 10/06/2025 8:41 pm, Andres Freund wrote:
> > I was able to reproduce it with gcc, too.
> > I've reproduced it without that bitfield, unfortunately :(.

> But also only at MacOS?

Correct.

> I wonder if it is possible to set hardware watchpoint fro program itself
> (not using gdb)? I.e. using ptrace?
> Looks like it is not possible to debug yourself:
> https://stackoverflow.com/questions/64321402/adding-a-watchpoint-in-the-current-process-not-in-gdb-not-for-debugging
>
> but it is possible to fork process.
> In theory it certainly should be possible - gdb is normal process, so at
> least we can implement our mini-gdb.
> But not sure how complex it will be.

If this were on intel, I would try to use intel-pt to get the execution trace
for the recent past at the time of the assertion failure, but it's not
intel...

FWIW, in all the incidents I looked at the actual read-in buffers are valid,
so it's not like the IO did not occur or such.

Greetings,

Andres Freund