From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id 52F706B0033 for ; Fri, 22 Sep 2017 10:56:28 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id t184so1781763qke.0 for ; Fri, 22 Sep 2017 07:56:28 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id l88si10736qte.337.2017.09.22.07.56.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 Sep 2017 07:56:26 -0700 (PDT) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v8MEtg4Q068226 for ; Fri, 22 Sep 2017 10:56:25 -0400 Received: from e15.ny.us.ibm.com (e15.ny.us.ibm.com [129.33.205.205]) by mx0a-001b2d01.pphosted.com with ESMTP id 2d54m9gc87-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 22 Sep 2017 10:56:24 -0400 Received: from localhost by e15.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 22 Sep 2017 10:56:23 -0400 From: Reza Arbab Subject: [PATCH] mm/device-public-memory: Fix edge case in _vm_normal_page() Date: Fri, 22 Sep 2017 09:56:18 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Message-Id: <1506092178-20351-1-git-send-email-arbab@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= With device public pages at the end of my memory space, I'm getting output from _vm_normal_page(): BUG: Bad page map in process migrate_pages pte:c0800001ffff0d06 pmd:f95d3000 addr:00007fff89330000 vm_flags:00100073 anon_vma:c0000000fa899320 mapping: (null) index:7fff8933 file: (null) fault: (null) mmap: (null) readpage: (null) CPU: 0 PID: 13963 Comm: migrate_pages Tainted: P B OE 4.14.0-rc1-wip #155 Call Trace: [c0000000f965f910] [c00000000094d55c] dump_stack+0xb0/0xf4 (unreliable) [c0000000f965f950] [c0000000002b269c] print_bad_pte+0x28c/0x340 [c0000000f965fa00] [c0000000002b59c0] _vm_normal_page+0xc0/0x140 [c0000000f965fa20] [c0000000002b6e64] zap_pte_range+0x664/0xc10 [c0000000f965fb00] [c0000000002b7858] unmap_page_range+0x318/0x670 [c0000000f965fbd0] [c0000000002b8074] unmap_vmas+0x74/0xe0 [c0000000f965fc20] [c0000000002c4a18] exit_mmap+0xe8/0x1f0 [c0000000f965fce0] [c0000000000ecbdc] mmput+0xac/0x1f0 [c0000000f965fd10] [c0000000000f62e8] do_exit+0x348/0xcd0 [c0000000f965fdd0] [c0000000000f6d2c] do_group_exit+0x5c/0xf0 [c0000000f965fe10] [c0000000000f6ddc] SyS_exit_group+0x1c/0x20 [c0000000f965fe30] [c00000000000b184] system_call+0x58/0x6c The pfn causing this is the very last one. Correct the bounds check accordingly. Fixes: df6ad69838fc ("mm/device-public-memory: device memory cache coherent with CPU") Cc: JA(C)rA'me Glisse Signed-off-by: Reza Arbab --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index ec4e154..a728bed 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -845,7 +845,7 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr, * vm_normal_page() so that we do not have to special case all * call site of vm_normal_page(). */ - if (likely(pfn < highest_memmap_pfn)) { + if (likely(pfn <= highest_memmap_pfn)) { struct page *page = pfn_to_page(pfn); if (is_device_public_page(page)) { -- 1.8.3.1 -- 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