From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa0-f51.google.com (mail-oa0-f51.google.com [209.85.219.51]) by kanga.kvack.org (Postfix) with ESMTP id 4C4416B0031 for ; Mon, 6 Jan 2014 23:34:44 -0500 (EST) Received: by mail-oa0-f51.google.com with SMTP id m1so2168388oag.10 for ; Mon, 06 Jan 2014 20:34:44 -0800 (PST) Received: from e28smtp05.in.ibm.com (e28smtp05.in.ibm.com. [122.248.162.5]) by mx.google.com with ESMTPS id so9si58193003oeb.114.2014.01.06.20.34.41 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 06 Jan 2014 20:34:43 -0800 (PST) Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 7 Jan 2014 10:04:39 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 8B917E0053 for ; Tue, 7 Jan 2014 10:07:21 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s074YUmS63832156 for ; Tue, 7 Jan 2014 10:04:30 +0530 Received: from d28av02.in.ibm.com (localhost [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s074YZBO028306 for ; Tue, 7 Jan 2014 10:04:36 +0530 Date: Tue, 7 Jan 2014 12:34:34 +0800 From: Wanpeng Li Subject: Re: could you clarify mm/mempolicy: fix !vma in new_vma_page() Message-ID: <52cb83e3.c9903c0a.614e.1751SMTPIN_ADDED_BROKEN@mx.google.com> Reply-To: Wanpeng Li References: <20140106112422.GA27602@dhcp22.suse.cz> <20140106141827.GB27602@dhcp22.suse.cz> <52cb81ed.e3d8420a.72a1.ffffea65SMTPIN_ADDED_BROKEN@mx.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52cb81ed.e3d8420a.72a1.ffffea65SMTPIN_ADDED_BROKEN@mx.google.com> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Sasha Levin , Bob Liu , Naoya Horiguchi , Bob Liu , Linux-MM , LKML Cced Sasha, On Tue, Jan 07, 2014 at 12:26:13PM +0800, Wanpeng Li wrote: >Hi Michal, >On Mon, Jan 06, 2014 at 03:18:27PM +0100, Michal Hocko wrote: >>On Mon 06-01-14 20:45:54, Bob Liu wrote: >>[...] >>> 544 if (PageAnon(page)) { >>> 545 struct anon_vma *page__anon_vma = page_anon_vma(page); >>> 546 /* >>> 547 * Note: swapoff's unuse_vma() is more efficient with this >>> 548 * check, and needs it to match anon_vma when KSM is active. >>> 549 */ >>> 550 if (!vma->anon_vma || !page__anon_vma || >>> 551 vma->anon_vma->root != page__anon_vma->root) >>> 552 return -EFAULT; >>> 553 } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { >>> 554 if (!vma->vm_file || >>> 555 vma->vm_file->f_mapping != page->mapping) >>> 556 return -EFAULT; >>> 557 } else >>> 558 return -EFAULT; >>> >>> That's the "other conditions" and the reason why we can't use >>> BUG_ON(!vma) in new_vma_page(). >> >>Sorry, I wasn't clear with my question. I was interested in which of >>these triggered and why only for hugetlb pages? > >Not just for hugetlb pages, sorry for do two things in one patch. The change >for hugetlb pages is to fix the potential dereference NULL pointer reported >by Dan. http://marc.info/?l=linux-mm&m=137689530323257&w=2 > >If we should ask Sasha to add more debug information to dump which condition >is failed in page_address_in_vma() for you? > >Regards, >Wanpeng Li > > >> >>-- >>Michal Hocko >>SUSE Labs > >-- >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 -- 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