From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f45.google.com (mail-pa0-f45.google.com [209.85.220.45]) by kanga.kvack.org (Postfix) with ESMTP id D7E956B0132 for ; Fri, 18 Oct 2013 07:21:15 -0400 (EDT) Received: by mail-pa0-f45.google.com with SMTP id rd3so4381163pab.18 for ; Fri, 18 Oct 2013 04:21:15 -0700 (PDT) Received: from psmtp.com ([74.125.245.130]) by mx.google.com with SMTP id hj4si1252326pac.39.2013.10.18.04.21.14 for ; Fri, 18 Oct 2013 04:21:14 -0700 (PDT) From: "Kirill A. Shutemov" In-Reply-To: <1382084117-25599-1-git-send-email-linx.z.chen@intel.com> References: <1382084117-25599-1-git-send-email-linx.z.chen@intel.com> Subject: RE: [PATCH] mm/pagewalk.c: Fix walk_page_range access wrong PTEs Content-Transfer-Encoding: 7bit Message-Id: <20131018112042.AD31EE0090@blue.fi.intel.com> Date: Fri, 18 Oct 2013 14:20:42 +0300 (EEST) Sender: owner-linux-mm@kvack.org List-ID: To: linx.z.chen@intel.com Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, cpw@sgi.com, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, yanmin_zhang@linux.intel.com, shuox.liu@intel.com linx.z.chen@ wrote: > From: Chen LinX > > When walk_page_range walk a memory map's page tables, it'll skip VM_PFNMAP area, > then variable 'next' will to assign to vma->vm_end, it maybe larger than 'end'. > In next loop, 'addr' will be larger than 'next'. Then in /proc/XXXX/pagemap file > reading procedure, the 'addr' will growing forever in pagemap_pte_range, > pte_to_pagemap_entry will access wrong pte. > > [ 93.387934] BUG: Bad page map in process procrank pte:8437526f pmd:785de067 > [ 93.387936] addr:9108d000 vm_flags:00200073 anon_vma:f0d99020 mapping: (null) index:9108d > [ 93.387938] CPU: 1 PID: 4974 Comm: procrank Tainted: G B W O 3.10.1+ #1 > [ 93.387942] f0d983c8 f0d983c8 e8271e48 c281ef4b e8271e84 c20ee794 c2a3f150 9108d000 > [ 93.387946] 00200073 f0d99020 00000000 0009108d e8342d90 8437526f 0009108d 00000000 > [ 93.387950] 00000000 00084375 fffa4234 e8271e98 c20ef836 00000000 e8271f28 f0d983c8 > [ 93.387951] Call Trace: > [ 93.387953] [] dump_stack+0x16/0x18 > [ 93.387956] [] print_bad_pte+0x114/0x1b0 > [ 93.387959] [] vm_normal_page+0x56/0x60 > [ 93.387961] [] pagemap_pte_range+0x17a/0x1d0 > [ 93.387963] [] ? m_next+0x70/0x70 > [ 93.387966] [] walk_page_range+0x19e/0x2c0 > [ 93.387969] [] ? ptrace_may_access+0x24/0x40 > [ 93.387971] [] pagemap_read+0x16e/0x200 > [ 93.387973] [] ? m_next+0x70/0x70 > [ 93.387976] [] ? quota_send_warning+0x1f0/0x1f0 > [ 93.387979] [] ? pagemap_pte_hole+0x50/0x50 > [ 93.387981] [] ? clear_refs_pte_range+0xc0/0xc0 > [ 93.387984] [] vfs_read+0x84/0x150 > [ 93.387986] [] ? clear_refs_pte_range+0xc0/0xc0 > [ 93.387988] [] SyS_read+0x4a/0x80 > [ 93.387991] [] syscall_call+0x7/0xb > [ 93.387996] [] ? e1000_regdump+0x6f/0x37c > [ 102.866190] [] ? cpuidle_idle_call+0x93/0x1b0 > [ 102.872124] [] ? atomic_notifier_call_chain+0x1a/0x20 > [ 102.878834] [] ? arch_cpu_idle+0x8/0x20 > [ 102.884183] [] ? cpu_startup_entry+0x4d/0x1b0 > [ 102.890116] [] ? rest_init+0x5d/0x60 > [ 102.895174] [] ? start_kernel+0x31b/0x321 > [ 102.900717] [] ? repair_env_string+0x51/0x51 > [ 102.906551] [] ? i386_start_kernel+0x12c/0x12f > > Signed-off-by: Liu ShuoX > Signed-off-by: Chen LinX Looks reasonable for me. Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org