From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753324AbeDQN1X (ORCPT ); Tue, 17 Apr 2018 09:27:23 -0400 Received: from 8bytes.org ([81.169.241.247]:52192 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752779AbeDQN1W (ORCPT ); Tue, 17 Apr 2018 09:27:22 -0400 From: Joerg Roedel To: Thomas Gleixner , Ingo Molnar Cc: hpa@zytor.com, x86@kernel.org, kirill.shutemov@linux.intel.com, jgross@suse.com, JBeulich@suse.com, aryabinin@virtuozzo.com, linux-kernel@vger.kernel.org, Joerg Roedel Subject: [PATCH] x86/mm: Fix kernel oops in PTDUMP code with HIGHPTE=y Date: Tue, 17 Apr 2018 15:27:16 +0200 Message-Id: <1523971636-4137-1-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel 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 nd fix the oops. Fixes: fe770bf0310d ('x86: clean up the page table dumper and add 32-bit support') Signed-off-by: Joerg Roedel --- arch/x86/mm/dump_pagetables.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 956c886f5dff..db1d7a0e6335 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -18,6 +18,7 @@ #include #include #include +#include #include @@ -344,16 +345,16 @@ static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr, pgprotval_t eff_in, unsigned long P) { int i; - pte_t *start; + pte_t *pte; pgprotval_t prot, eff; - start = (pte_t *)pmd_page_vaddr(addr); for (i = 0; i < PTRS_PER_PTE; i++) { - prot = pte_flags(*start); - eff = effective_prot(eff_in, prot); st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT); + pte = pte_offset_map(&addr, st->current_address); + prot = pte_flags(*pte); + eff = effective_prot(eff_in, prot); note_page(m, st, __pgprot(prot), eff, 5); - start++; + pte_unmap(pte); } } #ifdef CONFIG_KASAN -- 2.13.6