Re: [BUGFIX/x86] Fix initialization of wakeup_cpu.

[Yinghai Lu]

Alok Kataria wrote:
> On Tue, 2009-02-10 at 13:03 -0800, Yinghai Lu wrote:
>> On Tue, Feb 10, 2009 at 12:28 PM, Alok Kataria <akataria@xxxxxxxxxx> wrote:
>>> Was originally reported in the..
>>> "Re: [PARAVIRT/x86] BUGFIX: Put a missing paravirt_release_pmd in pgd_dtor" thread
>>>
>>> --
>>> With the patches for refactoring of wake_cpu macros, the 32bit code
>>> in tip doesn't execute generic_apic_probe if CONFIG_X86_32_NON_STANDARD
>>> is not set.
>>>
>>> Even on a x86 STANDARD cpu we need to execute the generic_apic_probe
>>> function, as we rely on this function to execute the update_genapic
>>> quirk which initilizes apic->wakeup_cpu.
>>>
>>> Failing to do so results in we making a call to a null function in do_boot_cpu.
>>>
>>> The stack trace without the patch goes like this.
>>>
>>> Booting processor 1 APIC 0x1 ip 0x6000
>>> BUG: unable to handle kernel NULL pointer dereference at (null)
>>> IP: [<(null)>] (null)
>>> *pdpt = 0000000000839001 *pde = 0000000000c97067 *pte = 0000000000000163
>>> Oops: 0000 [#1] SMP
>>> last sysfs file:
>>> Modules linked in:
>>>
>>> Pid: 1, comm: swapper Not tainted (2.6.29-rc4-tip #18) VMware Virtual Platform
>>> EIP: 0062:[<00000000>] EFLAGS: 00010293 CPU: 0
>>> EIP is at 0x0
>>> EAX: 00000001 EBX: 00006000 ECX: c077ed00 EDX: 00006000
>>> ESI: 00000001 EDI: 00000001 EBP: ef04cf40 ESP: ef04cf1c
>>>  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 006a
>>> Process swapper (pid: 1, ti=ef04c000 task=ef050000 task.ti=ef04c000)
>>> Stack:
>>>  c0644e52 00000000 ef04cf24 ef04cf24 c064468d c0886dc0 00000000 c0702aea
>>>  ef055480 00000001 00000101 dead4ead ffffffff ffffffff c08af530 00000000
>>>  c0709715 ef04cf60 ef04cf60 00000001 00000000 00000000 dead4ead ffffffff
>>> Call Trace:
>>>  [<c0644e52>] ? native_cpu_up+0x2de/0x45b
>>>  [<c064468d>] ? do_fork_idle+0x0/0x19
>>>  [<c0645c5e>] ? _cpu_up+0x88/0xe8
>>>  [<c0645d20>] ? cpu_up+0x42/0x4e
>>>  [<c07e7462>] ? kernel_init+0x99/0x14b
>>>  [<c07e73c9>] ? kernel_init+0x0/0x14b
>>>  [<c040375f>] ? kernel_thread_helper+0x7/0x10
>>> Code:  Bad EIP value.
>>> EIP: [<00000000>] 0x0 SS:ESP 006a:ef04cf1c
>>>
>>> I think we should call generic_apic_probe unconditionally now.
>>>
>>> Signed-off-by: Alok N Kataria <akataria@xxxxxxxxxx>
>>>
>>> Index: linux-tip-master/arch/x86/kernel/setup.c
>>> ===================================================================
>>> --- linux-tip-master.orig/arch/x86/kernel/setup.c       2009-02-10 11:37:31.000000000 -0800
>>> +++ linux-tip-master/arch/x86/kernel/setup.c    2009-02-10 11:50:37.000000000 -0800
>>> @@ -936,9 +936,7 @@
>>>        map_vsyscall();
>>>  #endif
>>>
>>> -#if defined(CONFIG_X86_32_NON_STANDARD) || defined(CONFIG_X86_BIGSMP)
>>>        generic_apic_probe();
>>> -#endif
>>>
>>>        early_quirks();
>>>
>> 1. only es7000 and numaq has update_genapic() ==> they need
>> X86_32_NON_STANDARD..
> 
> 
> There is one here too 
> 
> static struct x86_quirks default_x86_quirks __initdata = {
>         .update_genapic         = default_update_genapic,
> }
> 
>> 2. also will break 64 bit....
> isn't the default_x86_quirks defined for 64 bit too ? 
> 
64 bit doesn't have genapic_apic_probe()

need to change that to 
#ifdef CONFIG_X86_32
	genapic_apic_probe();
#endif

YH
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