From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f172.google.com (mail-wi0-f172.google.com [209.85.212.172]) by kanga.kvack.org (Postfix) with ESMTP id 649366B0031 for ; Fri, 14 Feb 2014 10:10:27 -0500 (EST) Received: by mail-wi0-f172.google.com with SMTP id e4so562671wiv.11 for ; Fri, 14 Feb 2014 07:10:26 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTP id k10si4114348wjb.29.2014.02.14.07.10.24 for ; Fri, 14 Feb 2014 07:10:25 -0800 (PST) Date: Fri, 14 Feb 2014 10:09:58 -0500 From: Naoya Horiguchi Message-ID: <52fe31e1.ca0ac20a.5647.5e12SMTPIN_ADDED_BROKEN@mx.google.com> In-Reply-To: <20140214130450.GA14755@localhost> References: <52fdd350.dwn4aII31EyWlDq9%fengguang.wu@intel.com> <20140214130450.GA14755@localhost> Subject: [PATCH] fs/proc/task_mmu.c: assume non-NULL vma in pagemap_hugetlb() (Re: [mmotm:master 97/220] fs/proc/task_mmu.c:1042 pagemap_hugetlb() error: we previously assumed 'vma' could be null (see line 1037)) Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Fengguang Wu Cc: kbuild-all@01.org, Johannes Weiner , Andrew Morton , Linux Memory Management List Hi Fengguang, On Fri, Feb 14, 2014 at 09:04:50PM +0800, Fengguang Wu wrote: ... > FYI, there are new smatch warnings show up in > > tree: git://git.cmpxchg.org/linux-mmotm.git master > head: 0363f94bc1c9b81f23ee7d2446331eb288568ea7 > commit: 81272031cc2831a3d1abb3c681f1188aa36a1454 [97/220] pagewalk: remove argument hmask from hugetlb_entry() > > fs/proc/task_mmu.c:1042 pagemap_hugetlb() error: we previously assumed 'vma' could be null (see line 1037) > > vim +/vma +1042 fs/proc/task_mmu.c > > d9104d1c Cyrill Gorcunov 2013-09-11 1031 int flags2; > 16fbdce6 Konstantin Khlebnikov 2012-05-10 1032 pagemap_entry_t pme; > 81272031 Naoya Horiguchi 2014-02-13 1033 unsigned long hmask; > 5dc37642 Naoya Horiguchi 2009-12-14 1034 > d9104d1c Cyrill Gorcunov 2013-09-11 1035 WARN_ON_ONCE(!vma); > d9104d1c Cyrill Gorcunov 2013-09-11 1036 > d9104d1c Cyrill Gorcunov 2013-09-11 @1037 if (vma && (vma->vm_flags & VM_SOFTDIRTY)) > d9104d1c Cyrill Gorcunov 2013-09-11 1038 flags2 = __PM_SOFT_DIRTY; > d9104d1c Cyrill Gorcunov 2013-09-11 1039 else > d9104d1c Cyrill Gorcunov 2013-09-11 1040 flags2 = 0; > d9104d1c Cyrill Gorcunov 2013-09-11 1041 > 21a2f342 Naoya Horiguchi 2014-02-13 @1042 hmask = huge_page_mask(hstate_vma(vma)); > 5dc37642 Naoya Horiguchi 2009-12-14 1043 for (; addr != end; addr += PAGE_SIZE) { > 116354d1 Naoya Horiguchi 2010-04-06 1044 int offset = (addr & ~hmask) >> PAGE_SHIFT; > d9104d1c Cyrill Gorcunov 2013-09-11 1045 huge_pte_to_pagemap_entry(&pme, pm, *pte, offset, flags2); Thanks for reporting, here is a patch. We never have NULL vma in pagemap_hugetlb(), I added the BUG_ON check. Thanks, Naoya Horiguchi --- From: Naoya Horiguchi Date: Fri, 14 Feb 2014 09:35:06 -0500 Subject: [PATCH] fs/proc/task_mmu.c: assume non-NULL vma in pagemap_hugetlb() Fengguang reported smatch error about potential NULL pointer access. In updated page table walker, we never run ->hugetlb_entry() callback on the address without vma. This is because __walk_page_range() checks it in advance. So we can assume non-NULL vma in pagemap_hugetlb(). Reported-by: Fengguang Wu Signed-off-by: Naoya Horiguchi --- fs/proc/task_mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index f819d0d4a0e8..69aed7192254 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1032,9 +1032,9 @@ static int pagemap_hugetlb(pte_t *pte, unsigned long addr, unsigned long end, pagemap_entry_t pme; unsigned long hmask; - WARN_ON_ONCE(!vma); + BUG_ON(!vma); - if (vma && (vma->vm_flags & VM_SOFTDIRTY)) + if (vma->vm_flags & VM_SOFTDIRTY) flags2 = __PM_SOFT_DIRTY; else flags2 = 0; -- 1.8.5.3 -- 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