lkml.org 
[lkml]   [2008]   [Jan]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH CPA] [21/28] CPA: Dump pagetable when inconsistency is detected
    Date

    When c_p_a() detects a inconsistency in the kernel page tables
    it BUGs. When this happens dump the page table first to avoid one
    bug reporting round trip.

    Signed-off-by: Andi Kleen <ak@suse.de>

    ---
    arch/x86/mm/pageattr_32.c | 11 ++++++++++-
    arch/x86/mm/pageattr_64.c | 11 ++++++++++-
    2 files changed, 20 insertions(+), 2 deletions(-)

    Index: linux/arch/x86/mm/pageattr_64.c
    ===================================================================
    --- linux.orig/arch/x86/mm/pageattr_64.c
    +++ linux/arch/x86/mm/pageattr_64.c
    @@ -12,6 +12,7 @@
    #include <asm/processor.h>
    #include <asm/tlbflush.h>
    #include <asm/io.h>
    +#include <asm/kdebug.h>

    enum flush_mode { FLUSH_NONE, FLUSH_CACHE, FLUSH_TLB };

    @@ -231,8 +232,16 @@ __change_page_attr(unsigned long address
    set_pte(kpte, pfn_pte(pfn, ref_prot));
    BUG_ON(page_private(kpte_page) == 0);
    page_private(kpte_page)--;
    - } else
    + } else {
    + /*
    + * When you're here you either did set the same page to PAGE_KERNEL
    + * two times in a row or the page table reference counting is broken again.
    + * To catch the later bug for now (sorry)
    + */
    + printk(KERN_ERR "address %lx\n", address);
    + dump_pagetable(address);
    BUG();
    + }

    /* on x86-64 the direct mapping set at boot is not using 4k pages */
    BUG_ON(PageReserved(kpte_page));
    Index: linux/arch/x86/mm/pageattr_32.c
    ===================================================================
    --- linux.orig/arch/x86/mm/pageattr_32.c
    +++ linux/arch/x86/mm/pageattr_32.c
    @@ -13,6 +13,7 @@
    #include <asm/tlbflush.h>
    #include <asm/pgalloc.h>
    #include <asm/sections.h>
    +#include <asm/kdebug.h>

    #define PG_deferred PG_arch_1

    @@ -252,8 +253,16 @@ __change_page_attr(struct page *page, pg
    set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
    BUG_ON(page_private(kpte_page) == 0);
    page_private(kpte_page)--;
    - } else
    + } else {
    + /*
    + * When you're here you either did set the same page to PAGE_KERNEL
    + * two times in a row or the page table reference counting is broken again.
    + * To catch the later bug for now (sorry)
    + */
    + printk(KERN_ERR "address %lx\n", address);
    + dump_pagetable(address);
    BUG();
    + }

    /*
    * If the pte was reserved, it means it was created at boot

    \
     
     \ /
      Last update: 2008-01-03 16:35    [W:0.024 / U:3.192 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site