From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f45.google.com (mail-ee0-f45.google.com [74.125.83.45]) by kanga.kvack.org (Postfix) with ESMTP id D0F1C6B0031 for ; Mon, 13 Jan 2014 11:33:05 -0500 (EST) Received: by mail-ee0-f45.google.com with SMTP id d49so3305041eek.4 for ; Mon, 13 Jan 2014 08:33:05 -0800 (PST) Received: from jenni2.inet.fi (mta-out.inet.fi. [195.156.147.13]) by mx.google.com with ESMTP id d46si20225397eeo.60.2014.01.13.08.33.01 for ; Mon, 13 Jan 2014 08:33:05 -0800 (PST) Date: Mon, 13 Jan 2014 18:32:54 +0200 From: "Kirill A. Shutemov" Subject: Re: [PATCH V4] powerpc: thp: Fix crash on mremap Message-ID: <20140113163254.GA4658@node.dhcp.inet.fi> References: <1389593064-32664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389593064-32664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Aneesh Kumar K.V" Cc: benh@kernel.crashing.org, paulus@samba.org, aarcange@redhat.com, kirill.shutemov@linux.intel.com, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org On Mon, Jan 13, 2014 at 11:34:24AM +0530, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" > > This patch fix the below crash > > NIP [c00000000004cee4] .__hash_page_thp+0x2a4/0x440 > LR [c0000000000439ac] .hash_page+0x18c/0x5e0 > ... > Call Trace: > [c000000736103c40] [00001ffffb000000] 0x1ffffb000000(unreliable) > [437908.479693] [c000000736103d50] [c0000000000439ac] .hash_page+0x18c/0x5e0 > [437908.479699] [c000000736103e30] [c00000000000924c] .do_hash_page+0x4c/0x58 > > On ppc64 we use the pgtable for storing the hpte slot information and > store address to the pgtable at a constant offset (PTRS_PER_PMD) from > pmd. On mremap, when we switch the pmd, we need to withdraw and deposit > the pgtable again, so that we find the pgtable at PTRS_PER_PMD offset > from new pmd. > > We also want to move the withdraw and deposit before the set_pmd so > that, when page fault find the pmd as trans huge we can be sure that > pgtable can be located at the offset. > > Signed-off-by: Aneesh Kumar K.V 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