Re: [PATCH] sparc64: fix hugetlb for sun4u

[John Paul Adrian Glaubitz]

On Sat, 2025-08-09 at 08:23 +0200, John Paul Adrian Glaubitz wrote:
> Hi Anthony,
> 
> On Sat, 2025-08-09 at 00:37 +0200, John Paul Adrian Glaubitz wrote:
> > > Maybe try enabling CONFIG_DEBUG_VM_IRQSOFF, CONFIG_DEBUG_VM, and perhaps 
> > > CONFIG_DEBUG_VM_PGFLAGS. That might help detect a problem closer to the 
> > > source. You can also try adding transparent_hugepage=never to the kernel 
> > > boot line to see if compiling in THP support but not using it is okay.
> > 
> > OK, I will try that. But not today anymore. It's half past midnight now here in Germany
> > and I was debugging this issue almost all day long. I'm glad to have finally been able
> > to track this down to THP support being enabled.
> > 
> > Maybe you can try whether you can reproduce this in QEMU as well.
> 
> OK, first data point: Setting CONFIG_TRANSPARENT_HUGEPAGE_NEVER=y causes the backtrace during
> boot to disappear with CONFIG_TRANSPARENT_HUGEPAGE=y. However, it still disappears later when
> running "apt update && apt -y upgrade" again:

That was meant to say "it appears later", of course.

So, again. No backtrace during boot with CONFIG_TRANSPARENT_HUGEPAGE_NEVER=y but later when
running apt.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913