[Crash-utility] [PATCH] Fix reading x86_64 xendump cores on 2.6.27+

[Dave Anderson]

----- "Petr Tesarik" <ptesarik at suse.cz> wrote:

> Hi,
> 
> the crash utility is unable to read xendump cores from kernel versions
> 2.6.27 or newer. Bernhard fixed this only for kdump Xen cores.
> 
> With 2.6.27 and newer kernels, the max_pfn symbol should be used
> to get the highest PFN in the system. However, xendump code still
> tries to use end_pfn. Without the patch, early initialization
> fails with the error message: "crash: cannot resolve "end_pfn".
> 
> Signed-off-by: Petr Tesarik <ptesarik at suse.cz>

Looks good to me -- queued for next release.

Thanks,
  Dave

> 
> ---
>  x86_64.c |   22 ++++++++++++++++++++--
>  1 file changed, 20 insertions(+), 2 deletions(-)
> 
> --- a/x86_64.c
> +++ b/x86_64.c
> @@ -4851,6 +4851,7 @@ x86_64_xen_kdump_p2m_create(struct xen_k
>          ulong frames;
>          ulong frame_mfn[MAX_X86_64_FRAMES] = { 0 };
>          int mfns[MAX_X86_64_FRAMES] = { 0 };
> +	struct syment *sp;
>  
>          /*
>           *  Temporarily read physical (machine) addresses from vmcore
> by
> @@ -4932,7 +4933,15 @@ use_cr3:
>                  x86_64_debug_dump_page(fp, machdep->machspec->pml4,
>                          "contents of PML4 page:");
>  
> -	kvaddr = symbol_value("end_pfn");
> +	/*
> +	 * kernel version <  2.6.27 => end_pfn
> +	 * kernel version >= 2.6.27 => max_pfn
> +	 */
> +	if ((sp = symbol_search("end_pfn")))
> +		kvaddr = sp->value;
> +	else
> +		kvaddr = symbol_value("max_pfn");
> +
>          if (!x86_64_xen_kdump_load_page(kvaddr, xkd->page))
>                  return FALSE;
>          up = (ulong *)(xkd->page + PAGEOFFSET(kvaddr));
> @@ -5262,6 +5271,7 @@ x86_64_xendump_p2m_create(struct xendump
>  	ulong mfn, kvaddr, ctrlreg[8], ctrlreg_offset;
>  	ulong *up;
>  	off_t offset; 
> +	struct syment *sp;
>  
>          if (!symbol_exists("phys_to_machine_mapping")) {
>                  xd->flags |= XC_CORE_NO_P2M;
> @@ -5299,7 +5309,15 @@ x86_64_xendump_p2m_create(struct xendump
>  		x86_64_debug_dump_page(xd->ofp, machdep->machspec->pml4, 
>                  	"contents of PML4 page:");
>  
> -	kvaddr = symbol_value("end_pfn");
> +	/*
> +	 * kernel version <  2.6.27 => end_pfn
> +	 * kernel version >= 2.6.27 => max_pfn
> +	 */
> +	if ((sp = symbol_search("end_pfn")))
> +		kvaddr = sp->value;
> +	else
> +		kvaddr = symbol_value("max_pfn");
> +
>  	if (!x86_64_xendump_load_page(kvaddr, xd))
>  		return FALSE;
>  
> 
> 
> --
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