On Wed, 13 May 2020 18:15:57 +0200
Sven Schnelle <sv...@linux.ibm.com> wrote:
> Thanks for looking into this. I've attached my /proc/config.gz to this Mail.
> The x86 system is my Laptop which is a Thinkpad X280 with 4 HT CPUs (so 8 cpus
> in total). I've tried disabling preemption, but this didn't help.
>
> It's always this check that causes the loop:
>
> if (iter->head >= rb_page_size(iter->head_page)) {
> rb_inc_iter(iter);
> goto again;
> }
>
> On the first loop iter->head is some value > 0 and rb_page_size returns
> 0, afterwards it gets twice to this check with both values 0. The third
> time the warning is triggered. Maybe that information helps.
Letting it run long enough, I was able to trigger it.
I think I know what's wrong with it. I'll put in some debugging to see if
my thoughts are accurate.
Thanks for bringing this back to my attention.
-- Steve
