Re: new panic in 5.5-rc1 (parisc, kmem_cache_open)

[Jeroen Roovers <jer@gentoo.org>]

On Wed, 8 Jan 2020 05:05:24 -0500 (EST)
Mikulas Patocka <mpatocka@redhat.com> wrote:

> On Wed, 8 Jan 2020, Mike Rapoport wrote:
> 
> > On Tue, Jan 07, 2020 at 09:52:20AM -0500, Mikulas Patocka wrote:  
> > > 
> > > On Mon, 9 Dec 2019, Jeroen Roovers wrote:
> > >   
> > > > On Mon, 9 Dec 2019 20:22:17 +0200
> > > > Meelis Roos <mroos@linux.ee> wrote:
> > > >   
> > > > > I tried 5.5-rc1 on RP3440 and got a surprise panic on boot
> > > > > (5.4 worked):  
> > > > 
> > > > Ah, I was going to reported this, too.
> > > >   
> > > > > mem auto-init: stack:off, heap alloc:off, heap free:off
> > > > > Memory: 12348004K/12580864K available (6438K kernel code,
> > > > > 2148K rwdata, 954K rodata, 1193K init, 500K bss, 232860K
> > > > > reserved, 0K cma-reserved)  
> > > > 
> > > > I see an additional message after this:
> > > > 
> > > > random: get_random_u64 called from
> > > > __kmem_cache_create+0x70/0x660 with crng_init=0
> > > > 
> > > > And then the same or similar enough backtrace.
> > > > 
> > > > 
> > > > Regards,
> > > >      jer  
> > > 
> > > Hi
> > > 
> > > I also have this panic. I bisected it and it is caused by the
> > > patch d96885e277b5edcd1e474e8b1579005163f23dbe.  
> > 
> > My guess would be that pgd is not populated after the change.
> > Can you please check if the below hack fixes the crash?
> > 
> > 
> > diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
> > index ddca8287d43b..354cf060b67f 100644
> > --- a/arch/parisc/mm/init.c
> > +++ b/arch/parisc/mm/init.c
> > @@ -401,7 +401,7 @@ static void __init map_pages(unsigned long
> > start_vaddr, pmd = (pmd_t *) __pa(pmd);
> >  		}
> >  
> > -		pgd_populate(NULL, pg_dir, __va(pmd));
> > +		pud_populate(NULL, (pud_t *)pg_dir, __va(pmd));
> >  #endif
> >  		pg_dir++;
> >  
> >    
> 
> Test-by: Mikulas Patocka <mpatocka@redhat.com>
> 
> This patch fixes it.
> 
> Mikulas
> 

Fixes the issue on a C8000.

Tested-by: Jeroen Roovers <jer@gentoo.org>


Thanks,
     jer