Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH CPA] [21/28] CPA: Dump pagetable when inconsistency is detected | Date | Thu, 3 Jan 2008 16:24:36 +0100 (CET) |
| |
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
| |