Re: Early boot panic on machine with lots of memory

[Tejun Heo]

On Thu, Jun 14, 2012 at 11:50:40AM +0200, Sasha Levin wrote:
> On Thu, 2012-06-14 at 12:20 +0900, Tejun Heo wrote:
> > On Wed, Jun 13, 2012 at 11:38:55PM +0200, Sasha Levin wrote:
> > > Hi all,
> > > 
> > > I'm seeing the following when booting a KVM guest with 65gb of RAM, on latest linux-next.
> > > 
> > > Note that it happens with numa=off.
> > > 
> > > [    0.000000] BUG: unable to handle kernel paging request at ffff88102febd948
> > > [    0.000000] IP: [<ffffffff836a6f37>] __next_free_mem_range+0x9b/0x155
> > 
> > Can you map it back to the source line please?
> 
> mm/memblock.c:583
> 
>                         phys_addr_t r_start = ri ? r[-1].base + r[-1].size : 0;
>   97:   85 d2                   test   %edx,%edx
>   99:   74 08                   je     a3 <__next_free_mem_range+0xa3>
>   9b:   49 8b 48 f0             mov    -0x10(%r8),%rcx
>   9f:   49 03 48 e8             add    -0x18(%r8),%rcx
> 
> It's the deref on 9b (r8=ffff88102febd958).

* Can you please post disassembly of the whole function?  It seems
  like rsv->regions[] was corrupt.  I want to verify other registers
  too.

* Can you please try the following patch?

  https://lkml.org/lkml/2012/6/15/510

Thanks.

-- 
tejun
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