[Crash-utility] crash 4.0.9 on x86 is crashing

[Sumeet Gupta]

 Hi All,

I downloaded and built crash 4.0.9 for Intel X86 linux machine.
I'm trying to debug kdump-generated vmcore, taken using the "crash kernel".
Kernel: 2.6.27.34
Main kernel argument: crashkernel=64M at 16M
Main kernel loaded at 2M.

The problem:
./crash <vmlinux> <vmcore>
behaves kinda strange... it gets stuck in the following loop of function
calls, during reading totalram_pages symbol:
    get_symbol_data("totalram_pages") -> readmem("totalram_pages") ->kvtop
-> x86_kvtop ("pgd page") ->readmem ("pgd page") ->kvtop -> x86_kvtop("pgd
page") -> readmem("pgd page")

and eventually crashes, probably when recursion reaches stack limit.

Why would such a situation happen...?

With gdb, though, things are different - gdb is able to read the vmcore, and
give the gdb prompt, at which I can see the init_mm structure, and backtrace
etc. I also verified that pgd address (init_mm.pgd) is the same as crash is
trying to read through readmem("pgd page").

Any inputs will be very useful.

Thanks,
Sumeet
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