Re: 2.6.28-rc9 panics with crashkernel=256M while booting

From: Chandru <chandru@in.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: linuxppc-dev@ozlabs.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Paul Mackerras <paulus@samba.org>,
	linux-kernel@vger.kernel.org
Subject: Re: 2.6.28-rc9 panics with crashkernel=256M while booting
Date: Fri, 16 Jan 2009 17:46:36 +0530	[thread overview]
Message-ID: <200901161746.36584.chandru@in.ibm.com> (raw)
In-Reply-To: <200901151335.27649.chandru@in.ibm.com>

On Thursday 15 January 2009 13:35:27 Chandru wrote:
> Hello Dave, From the debug console output, if there is anything you can add
> here, pls let me know.

As we can see from the console output here,  physbase isn't page aligned when 
the panic occurs.  So we could as well send (start_pfn << PAGE_SHIFT) to 
reserve_bootmem_node() instead of physbase. your thoughts ?.

Also end_pfn in mark_reserved_region_for_nid() is defined as 

unsigned long end_pfn = ((physbase + size) >> PAGE_SHIFT);

Does this refer to the pfn after the area that we are interested in ?.  We have 
atleast two fixes here,  
1. Limit start and end to bdata->node_min_pfn  and bdata->node_low_pfn in 
reserve_bootmem_node() and add comments out in there that the caller of the 
funtion should be aware of how much are they reserving. 
2. send (start_pfn << PAGE_SHIFT) to reserve_bootmem_node() instead of 
physbase. 

Chandru