Messages in this thread | | | Date | Mon, 9 Oct 2006 10:53:58 +0100 (IST) | From | Mel Gorman <> | Subject | Re: 2.6.18-mm2 boot failure on x86-64 |
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On Fri, 6 Oct 2006, Vivek Goyal wrote:
> 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. >
It makes some sense. As you state, it wastes memory but that is better than breaking.
> Steve, can you please give this patch a try if it fixes the problem? >
I boottested the patch on the same machine as Steve was using and it completed successfully.
> 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 <vgoyal@in.ibm.com> > --- > > 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<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { > - *addrp = table_end << PAGE_SHIFT; > + *addrp = PAGE_ALIGN(table_end << PAGE_SHIFT); > return 1; > } > > @@ -68,18 +68,18 @@ static inline int bad_addr(unsigned long > #ifdef CONFIG_BLK_DEV_INITRD > if (LOADER_TYPE && INITRD_START && last >= 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) > _ >
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - 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/
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