3.16.60-rc1 review patch. If anyone has any objections, please let me know.
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From: Joerg Roedel jroedel@suse.de
commit d6ef1f194b7569af8b8397876dc9ab07649d63cb upstream.
The walk_pte_level() function just uses __va to get the virtual address of the PTE page, but that breaks when the PTE page is not in the direct mapping with HIGHPTE=y.
The result is an unhandled kernel paging request at some random address when accessing the current_kernel or current_user file.
Use the correct API to access PTE pages.
Fixes: fe770bf0310d ('x86: clean up the page table dumper and add 32-bit support') Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: jgross@suse.com Cc: JBeulich@suse.com Cc: hpa@zytor.com Cc: aryabinin@virtuozzo.com Cc: kirill.shutemov@linux.intel.com Link: https://lkml.kernel.org/r/1523971636-4137-1-git-send-email-joro@8bytes.org [bwh: Backported to 3.16: - Keep using pte_pgprot() to get protection flags - Adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -16,6 +16,7 @@ #include <linux/mm.h> #include <linux/module.h> #include <linux/seq_file.h> +#include <linux/highmem.h>
#include <asm/pgtable.h>
@@ -263,15 +264,16 @@ static void walk_pte_level(struct seq_fi unsigned long P) { int i; - pte_t *start; + pte_t *pte;
- start = (pte_t *) pmd_page_vaddr(addr); for (i = 0; i < PTRS_PER_PTE; i++) { - pgprot_t prot = pte_pgprot(*start); + pgprot_t prot;
st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT); + pte = pte_offset_map(&addr, st->current_address); + prot = pte_pgprot(*pte); note_page(m, st, prot, 4); - start++; + pte_unmap(pte); } }