Re: [crash] Re: [PATCH 0/4] x86_64: Optimize percpu accesses

Mike Travis
2008-07-28T19:39:30Z

Ingo Molnar wrote:
> ok, i have integrated tip/x86/percpu-zerobased into tip/master briefly,
> but it blew up almost immediately in testing, on two boxes.
>
> one bad config is:
>
> http://redhat.com/~mingo/misc/config-Mon_Jul_28_17_35_00_CEST_2008.bad
>
> failure pattern: it booted up fine to userspace and seemed function, but
> then produced a spontaneous reboot while building a kernel, without any
> log entries.
>
> other bad config is:
>
> http://redhat.com/~mingo/misc/config-Mon_Jul_28_17_30_39_CEST_2008.bad
>
> failure pattern: early crash at:
>
> PANIC: early exception 0e rip 10:fffffff817dfc1a error 0 cr2 28
>
> which corresponds to:
>
> ffffffff817dfc0f <machine_specific_memory_setup>:
> ffffffff817dfc0f: 48 8b 05 aa cf 04 00 mov 315306(%rip),%rax
> # ffffffff8182cbc0 <x86_quirks>
> ffffffff817dfc16: 55 push %rbp
> ffffffff817dfc17: 48 89 e5 mov %rsp,%rbp
> ffffffff817dfc1a: 48 8b 40 28 mov 0x28(%rax),%rax [*]
> ffffffff817dfc1e: 48 85 c0 test %rax,%rax
>
> i.e. RAX was zero.
>
> i've pushed out the tip/tmp.x86/percpu-zerobased.bad branch which shows
> the exact kernel that failed. It was generated by:
>
> git-checkout tip/master
> git-merge tip/x86/percpu-zerobased
>
> Ingo

Ok, thanks, I'll take a look. There were some questions that I had
(and I should have RFC'd the patch since there are still questions.)

Mike