[Crash-utility] [PATCH] ARM: fix segfault in page table read

[Mika Westerberg]

On Wed, Jan 18, 2012 at 09:07:29PM +0530, Rabin Vincent wrote:
> I have an ARM crash dump where the page tables have been corrupted.
> 
> crash segfaults while reading it because of a stack overflow due to recursion
> in the page table read core:
> 
> readmem: e2efcde0, KVADDR, "module unwind table", 24, (ROE), 8600bc0>
>     addr: e2efcde0  paddr: 22efcde0  cnt: 24
> <readmem: bf006550, KVADDR, "module unwind index table", 8, (ROE), 9ccab28>
> <readmem: c0004000, KVADDR, "pgd page", 16384, (FOE), 91c18e8>
>     addr: c0004000  paddr: 4000  cnt: 4096
>     addr: c0005000  paddr: 5000  cnt: 4096
>     addr: c0006000  paddr: 6000  cnt: 4096
>     addr: c0007000  paddr: 7000  cnt: 4096
> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0>
> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0>
> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0>
> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0>
> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0>
> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0>
> etc till segfault
> 
> The problem appears to be that the ARM code is attempting to PTOV() the
> physical address found in the page table and readmem() it as a KVADDR instead
> of just directly reading it as a PHYSADDR.

You are right - there's no point for doing PTOV() for those addreses. To me
this change looks good, thanks.

Acked-by: Mika Westerberg <mika.westerberg at iki.fi>