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

Yinghai Lu
2009-02-10T21:03:33Z

On Tue, Feb 10, 2009 at 12:28 PM, Alok Kataria <akataria@vmware.com> 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@vmware.com>
>
> 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..
2. also will break 64 bit....

YH