Re: Linux 6.11-rc1

From: Peter Zijlstra
Date: Tue Jul 30 2024 - 16:10:10 EST


On Tue, Jul 30, 2024 at 01:04:49PM -0700, Guenter Roeck wrote:
> On 7/30/24 12:38, Peter Zijlstra wrote:
> > On Tue, Jul 30, 2024 at 01:31:18PM -0600, Jens Axboe wrote:
> > > On 7/30/24 1:22 PM, Peter Zijlstra wrote:
> > > > On Tue, Jul 30, 2024 at 11:53:31AM -0700, Linus Torvalds wrote:
> > > >
> > > > > Which makes me think it's asm_exc_int3 just recursively failing.
> > > >
> > > > Sounds like text_poke() going sideways, there's a jump_label fail out
> > > > there:
> > > >
> > > > https://lkml.kernel.org/r/20240730132626.GV26599@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > >
> > > No change with this applied...
> > >
> > > Also not sure if you read my link, but a few things to note:
> > >
> > > - It only happens with gcc-11 here. I tried 12/13/14 and those
> > > are fine, don't have anything older
> >
> > One of my test boxes has 4.4 4.6 4.8 4.9 5 6 8 9 10 11 12 13
> >
> > (now I gotta go figure out wth 7 went :-) And yeah, we don't support
> > most of those version anymore (phew).
> >
> > So if its easy to setup, I could try older GCCs.
> >
>
> WFM with gcc 9.4, 10.3, 12.4, and 13.3. gcc 11.4 and 11.5 both fail.

10.5 and 13.2 worked for me, and I can confirm 11.4 makes it go boom.

> Maybe I should just switch to a more recent version of gcc and call it a day,
> in the hope that it is a compiler (or qemu) problem and doesn't just hide
> the problem.
>
> Thoughts ?

Tempting, but I think it would be good to figure out what in GCC-11
makes it sad, gcc-11 is still well within the supported range of GCCs
afaik.

Lets see if its something that wants to be bisected.