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    SubjectRe: [discuss] [OOPS] powernow on smp dual core amd64
    Tom Duffy wrote:

    >On Mon, 2005-06-13 at 16:47 -0500, Langsdorf, Mark wrote:
    >>Okay, I think I have figured this out. During initialization,
    >>the cpufreq infrastruture only initializes the first core of
    >>each processor. When a request comes into the second core,
    >>it's data structre is unitialized and we get the null point
    >>The solution is to assign the pointer to the data structure for
    >>the first core to all the other cores.
    >>Tom, could you try this patch and see if it helps?
    >Yes! It fixed the panic. I get much further.
    >Unfortunately, after starting cpuspeed daemon, I get this:
    >Starting cpuspeed: [ OK ]
    >Starting pcmcia: Starting PCMCIA services:
    >CPU 6: Machine Check Exception: 4 Bank 4: b200000000070f0f
    >TSC 4129a3d70d
    >Kernel panic - not syncing: Machine check
    > <1>Unable to handle kernel NULL pointer dereference at 00000000000000ff RIP:

    asmlinkage void smp_call_function_interrupt(void)
    void (*func) (void *info) = call_data->func;
    void *info = call_data->info;
    int wait = call_data->wait;

    * Notify initiating CPU that I've grabbed the data and am
    * about to execute the function
    * At this point the info structure may be out of scope unless
    (*func)(info); <--- passed bogus data

    Looks like you jumped through a bogus function pointer. I'm guessing it
    has something to do with an unitialized IRQ vector for the CPU speed on
    one of the cores (simply because it seems somewhat plausible):

    extern u8 irq_vector[NR_IRQ_VECTORS];
    #define IO_APIC_VECTOR(irq) (irq_vector[irq])
    #define AUTO_ASSIGN -1

    So irq_vector[AUTO_ASSIGN] = 0xff which could have somehow made it into
    your function pointer.

    Just a theory.
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      Last update: 2005-06-14 01:30    [W:0.024 / U:23.900 seconds]
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