Re: [BUG] i386 2.6.18 cpu_up: attempt to bring up CPU 4 failed : kernel BUG at mm/slab.c:2698!

Andrew Morton
2006-09-22T00:41:42Z

On Thu, 21 Sep 2006 17:17:31 -0700
keith mannthey <kmannth@us.ibm.com> wrote:

> I wanted to just give 2.6.18 a spin and I tripped over something I
> didn't expect.
>
>
> cpu_up: attempt to bring up CPU 4 failed
> kfree_debugcheck: bad ptr c15f6000h.
> ------------[ cut here ]------------
> kernel BUG at mm/slab.c:2698!
> invalid opcode: 0000 [#1]
> SMP
> Modules linked in:
> CPU: 0
> EIP: 0060:[<c106ce51>] Not tainted VLI
> EFLAGS: 00010046 (2.6.18 #1)
> EIP is at kfree_debugcheck+0x7f/0x90
> eax: 00000028 ebx: 000015f6 ecx: c1025289 edx: c7653540
> esi: c15f6000 edi: c15f6000 ebp: c764af38 esp: c764af28
> ds: 007b es: 007b ss: 0068
> Process swapper (pid: 1, ti=c764a000 task=c7653540 task.ti=c764a000)
> Stack: c122c68d c15f6000 c1635000 00000004 c764af5c c106ef93 00000286
> c76a77d0
> 00000004 00000001 c1635000 00000004 00000004 c764af6c c10557f6
> c1274eac
> c12743dc c764af84 c1207467 00000004 c12734c0 00000004 00000004
> c764af98
> Call Trace:
> [<c106ef93>] kfree+0x24/0x1d8
> [<c10557f6>] pageset_cpuup_callback+0x40/0x58
> [<c1207467>] notifier_call_chain+0x20/0x31
> [<c1031530>] blocking_notifier_call_chain+0x1d/0x2d
> [<c103f80c>] cpu_up+0xb5/0xcf
> [<c1000372>] init+0x78/0x296
> [<c1002005>] kernel_thread_helper+0x5/0xb

I think we have two problems here:

a) CPU4 didn't come up. To diagnose that I think we'll need to ask you
to into cpu_up(), add debug printks to blocking_notifier_call_chain(),
work out which entry on that chain returned NOTIFY_BAD, then work out
why it did so.

b) pageset_cpuup_callback()'s CPU_UP_CANCELED path possibly hasn't been
tested before. I'd be guessing that we're not zeroing out the
zone.pageset[] array when the `struct zone' is first allocated, but I
don't immediately recall where that code lives.