[Crash-utility] Re: crash 4.0-8.9 w/ 2.6.30-rc6

[Dave Anderson]

----- "Mike Snitzer" <snitzer at redhat.com> wrote:

> Hi Dave,
> 
> crash is failing with the following when I try to throw a 2.6.30-rc6
> vmcore at it:
> 
> crash: invalid structure size: x8664_pda
>        FILE: x86_64.c  LINE: 584  FUNCTION: x86_64_cpu_pda_init()
> 
> [/usr/bin/crash] error trace: 449c7f => 4ce815 => 4d00cf => 50936d
> 
>   50936d: SIZE_verify+168
>   4d00cf: (undetermined)
>   4ce815: x86_64_init+3205
>   449c7f: main_loop+152
> 
> I can dig deeper but your help would be very much appreciated.
> 
> Mike

The venerable "been-there-since-the-beginning-of-x86_64" x8664_pda
data structure no longer exists.  It was a per-cpu array of a fundamental
data structure that things like "current", the per-cpu magic number, the
cpu number, the current kernel stack pointer, the per-cpu IRQ stack pointer,
etc. all came from:  

/* Per processor datastructure. %gs points to it while the kernel runs */
struct x8664_pda {
        struct task_struct *pcurrent;   /* Current process */
        unsigned long data_offset;      /* Per cpu data offset from linker address */
        unsigned long kernelstack;  /* top of kernel stack for current */
        unsigned long oldrsp;       /* user rsp for system call */
#if DEBUG_STKSZ > EXCEPTION_STKSZ
        unsigned long debugstack;   /* #DB/#BP stack. */
#endif
        int irqcount;               /* Irq nesting counter. Starts with -1 */
        int cpunumber;              /* Logical CPU number */
        char *irqstackptr;      /* top of irqstack */
        int nodenumber;             /* number of current node */
        unsigned int __softirq_pending;
        unsigned int __nmi_count;       /* number of NMI on this CPUs */
        int mmu_state;
        struct mm_struct *active_mm;
        unsigned apic_timer_irqs;
} ____cacheline_aligned_in_smp;

There have been upstream rumblings about replacing it with a more efficient
per-cpu implementation for some time now, but I haven't studied how the new
scheme works yet.  It will be a major re-work for the crash utility, so you're
pretty much out of luck for now.  (Try "gdb vmlinux vmcore" for basic info)

In the meantime, can you give me a copy of your vmcore?  (offline -- note that
I'm forwarding this to the crash-utility mailing list).  And I'll start working
on it.

Thanks,
  Dave