lkml.org 
[lkml]   [2007]   [Jun]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [BUG] sysrq-m oops
    Bob Picco wrote:
    > john stultz wrote: [Thu Jun 07 2007, 03:54:41PM EDT]
    > [snip]
    > john you are welcome.
    >
    > We aren't sampling for holes in memory. Thus we encounter a section hole with
    > empty section map pointer for SPARSEMEM and OOPs for show_mem. This issue
    > has been seen in 2.6.21, current git and current mm. The patch below
    > is for mainline and mm. It was boot tested for SPARSEMEM, current
    > VMEMMAP of Andy's in mm ml and DISCONTIGMEM. A slightly different patch
    > will be posted to stable for 2.6.21.
    >
    > Previous to commit f0a5a58aa812b31fd9f197c4ba48245942364eae memory_present
    > was called for node_start_pfn to node_end_pfn. This would cover the hole(s)
    > with reserved pages and valid sections. Most SPARSEMEM supported arches
    > do a pfn_valid check in show_mem before computing the page structure address.
    >
    > This issue was brought to my attention on IRC by Arnaldo Carvalho de Melo at
    > acme@redhat.com. Thanks to Arnaldo for testing.
    >
    > Signed-off-by: Bob Picco <bob.picco@hp.com>
    >
    > arch/x86_64/mm/init.c | 2 ++
    > 1 file changed, 2 insertions(+)
    >
    > Index: linux-2.6.22-rc4-mm1/arch/x86_64/mm/init.c
    > ===================================================================
    > --- linux-2.6.22-rc4-mm1.orig/arch/x86_64/mm/init.c 2007-06-06 12:59:26.000000000 -0400
    > +++ linux-2.6.22-rc4-mm1/arch/x86_64/mm/init.c 2007-06-07 11:14:31.000000000 -0400
    > @@ -79,6 +79,8 @@ void show_mem(void)
    > if (unlikely(i % MAX_ORDER_NR_PAGES == 0)) {
    > touch_nmi_watchdog();
    > }
    > + if (!pfn_valid(pgdat->node_start_pfn + i))
    > + continue;
    > page = pfn_to_page(pgdat->node_start_pfn + i);
    > total++;
    > if (PageReserved(page))

    Yes this is required with SPARSEMEM. Good spot.

    Acked-by: Andy Whitcroft <apw@shadowen.org>

    -apw
    -
    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/

    \
     
     \ /
      Last update: 2007-06-08 18:09    [W:0.026 / U:0.188 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site