On Thu, Mar 24, 2011 at 4:41 PM, Christoph Lameter <cl@linux.com> wrote:
> On Thu, 24 Mar 2011, Ingo Molnar wrote:
>
>> FYI, some sort of boot crash has snuck upstream in the last 24 hours:
>>
>>  BUG: unable to handle kernel paging request at ffff87ffc147e020
>>  IP: [<ffffffff811aa762>] this_cpu_cmpxchg16b_emu+0x2/0x1c
>
> Hmmm.. This is the fallback code for the case that the processor does not
> support cmpxchg16b.

How does alternative_io() work? Does it require
alternative_instructions() to be executed. If so, the fallback code
won't be active when we enter kmem_cache_init(). Is there any reason
check_bugs() is called so late during boot? Can we do something like
the totally untested attached patch?