Re: context switch within RCU read-side critical section in next-20260518+ with PREEMPT_RT

[Thomas Gleixner]

On Thu, May 21 2026 at 10:53, Mateusz Guzik wrote:
> On Thu, May 21, 2026 at 12:52:44AM +0200, Bert Karwatzki wrote:
>> With these reverts next-20260519 boots 30 times in a row without error, so
>> it appears that commit dc651e25a6d2 ("fs: RCU-ify filesystems list") causing the
>> error.
>> 
>
> I think the patch below will do the trick.
>
> If someone wonders how come the missing unlocks: the original patch had
> them in place, but when I was rebasing on top of the RCU-ifing commit I
> figured I'm going to do guard/scoped_guard in there as well. Later it
> started failing as the compiler did not like goto retry out of a scoped
> guard area and the unlocks did not come back.
>
> tl;dr there is definitely my bug here and it is most likely *the* bug

I was staring at the wrong commit then :)