Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422913AbWJFUFT (ORCPT ); Fri, 6 Oct 2006 16:05:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422916AbWJFUFS (ORCPT ); Fri, 6 Oct 2006 16:05:18 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:35558 "EHLO e35.co.us.ibm.com") by vger.kernel.org with ESMTP id S1422912AbWJFUFQ (ORCPT ); Fri, 6 Oct 2006 16:05:16 -0400 Date: Fri, 6 Oct 2006 16:04:36 -0400 From: Vivek Goyal To: Steve Fox , mel@skynet.ie Cc: Andi Kleen , Badari Pulavarty , Martin Bligh , Andrew Morton , lkml , netdev@vger.kernel.org, kmannth@us.ibm.com, Andy Whitcroft Subject: Re: 2.6.18-mm2 boot failure on x86-64 Message-ID: <20061006200436.GG19756@in.ibm.com> Reply-To: vgoyal@in.ibm.com References: <20060928014623.ccc9b885.akpm@osdl.org> <200610052105.00359.ak@suse.de> <1160080954.29690.44.camel@flooterbu> <200610052250.55146.ak@suse.de> <1160101394.29690.48.camel@flooterbu> <20061006143312.GB9881@skynet.ie> <20061006153629.GA19756@in.ibm.com> <20061006171105.GC9881@skynet.ie> <1160157830.29690.66.camel@flooterbu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1160157830.29690.66.camel@flooterbu> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3857 Lines: 104 On Fri, Oct 06, 2006 at 01:03:50PM -0500, Steve Fox wrote: > On Fri, 2006-10-06 at 18:11 +0100, Mel Gorman wrote: > > On (06/10/06 11:36), Vivek Goyal didst pronounce: > > > Where is bss placed in physical memory? I guess bss_start and bss_stop > > > from System.map will tell us. That will confirm that above memset step is > > > stomping over bss. Then we have to just find that somewhere probably > > > we allocated wrong physical memory area for bootmem allocator map. > > > > > > > BSS is at 0x643000 -> 0x777BC4 > > init_bootmem wipes from 0x777000 -> 0x8F7000 > > > > So the BSS bytes from 0x777000 ->0x777BC4 (which looks very suspiciously > > pile a page alignment of addr & PAGE_MASK) gets set to 0xFF. One possible > > fix is below. It adds a check in bad_addr() to see if the BSS section is > > about to be used for bootmap. It Seems To Work For Me (tm) and illustrates > > the source of the problem even if it's not the 100% correct fix. > > I was able to boot the machine with Mel's patch applied on top of > -git22. Please have a look at the attached patch. Does it make some sense. Steve, can you please give this patch a try if it fixes the problem? Thanks Vivek o Currently some code pieces assume that address returned by find_e820_area() are page aligned. But looks like find_e820_area() had no such intention and hence one might end up stomping over some of the data. One such case is bootmem allocator initialization code stomped over bss. o This patch modified find_e820_area() to return page aligned address. This might be little wasteful of memory but at the same time probably it is easier to handle page aligned memory. Signed-off-by: Vivek Goyal --- arch/x86_64/kernel/e820.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff -puN arch/x86_64/kernel/e820.c~x86_64-return-page-aligned-phy-addr-from-find-e820-area arch/x86_64/kernel/e820.c --- linux-2.6.19-rc1-1M/arch/x86_64/kernel/e820.c~x86_64-return-page-aligned-phy-addr-from-find-e820-area 2006-10-06 15:28:13.000000000 -0400 +++ linux-2.6.19-rc1-1M-root/arch/x86_64/kernel/e820.c 2006-10-06 15:44:45.000000000 -0400 @@ -54,13 +54,13 @@ static inline int bad_addr(unsigned long /* various gunk below that needed for SMP startup */ if (addr < 0x8000) { - *addrp = 0x8000; + *addrp = PAGE_ALIGN(0x8000); return 1; } /* direct mapping tables of the kernel */ if (last >= table_start<= INITRD_START && addr < INITRD_START+INITRD_SIZE) { - *addrp = INITRD_START + INITRD_SIZE; + *addrp = PAGE_ALIGN(INITRD_START + INITRD_SIZE); return 1; } #endif /* kernel code */ - if (last >= __pa_symbol(&_text) && last < __pa_symbol(&_end)) { - *addrp = __pa_symbol(&_end); + if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) { + *addrp = PAGE_ALIGN(__pa_symbol(&_end)); return 1; } if (last >= ebda_addr && addr < ebda_addr + ebda_size) { - *addrp = ebda_addr + ebda_size; + *addrp = PAGE_ALIGN(ebda_addr + ebda_size); return 1; } @@ -152,7 +152,7 @@ unsigned long __init find_e820_area(unsi continue; while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size) ; - last = addr + size; + last = PAGE_ALIGN(addr) + size; if (last > ei->addr + ei->size) continue; if (last > end) _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/