From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0A20C43381 for ; Wed, 13 Mar 2019 09:58:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8B2D12087C for ; Wed, 13 Mar 2019 09:58:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B2D12087C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E81848E0003; Wed, 13 Mar 2019 05:58:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E32138E0001; Wed, 13 Mar 2019 05:58:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D21178E0003; Wed, 13 Mar 2019 05:58:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id 788BB8E0001 for ; Wed, 13 Mar 2019 05:58:37 -0400 (EDT) Received: by mail-ed1-f69.google.com with SMTP id k6so686359edq.3 for ; Wed, 13 Mar 2019 02:58:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:date:from:to :cc:subject:message-id:references:mime-version:content-disposition :in-reply-to:user-agent; bh=yqKaVHBwD3P5KNO+JV43iFleGVoTdaDnvO1Yqf4vQmA=; b=EdzCO8EEXMvNHkFdIVKqRsjlyzzUJyrX7tsDdhJO/pPXZ9TaGct8d8o70XZzachMTN 9q8D2CzWYP6JNEyRqGdpHg4BVNtVPI+ozWfb+9EFHFZmrZr3G+n+ARB/br7sGJyzkivG cjUbmJWk8Vifz9yHhlz1/3CqCP0IJ0NUtRn56ka1qOVelgJVZEl5Us1yg5IXg3uq2d28 RtGWoOoivdcdbvnmEq9qBE783l2EPfEskj2mYp78vEyLMEBHyYlxXMcywIM+C/YUT3em jBTzqE97XgfvNfQf+l0xrzguMOXO6vGkjQHSKFsd/becxaaWCm28HOG4p2vxBs775c5N Lg/A== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of jack@suse.cz designates 195.135.220.15 as permitted sender) smtp.mailfrom=jack@suse.cz X-Gm-Message-State: APjAAAWQJ4ETPtHHj1hZp6TkmcltoR7hxpL6/IOLtvhHrpiwLYspNQ/2 m8t8KzA+vrGBvonG1G56ymqFlYdcABwu4dcr0x4WeimOaN/l2qqGWwrf+qEGo4Z7Qo0/DJ5w6am WSe9e/17MYtbaUAGK5N2VZE9hhzHCwrIK/8dOqb7caYO2hfT1LbEDDLNzYRxHz/eJ0w== X-Received: by 2002:a50:c9c7:: with SMTP id c7mr7278252edi.72.1552471117052; Wed, 13 Mar 2019 02:58:37 -0700 (PDT) X-Google-Smtp-Source: APXvYqw9yaoNediiqOVPIFv12uCUJUWZqiW6UyayZSEdTA8y7kcQVG+b3CTxso+U/m3E278/qPz/ X-Received: by 2002:a50:c9c7:: with SMTP id c7mr7278195edi.72.1552471115991; Wed, 13 Mar 2019 02:58:35 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1552471115; cv=none; d=google.com; s=arc-20160816; b=k1d65L6oX5BB7T5Edx+vMFfsA6TRSRQYs2P7UFa+rllTWk19dOWroP6LzF0/jtA6i2 Sc0b1KAp2t9QUPCOr5RMiQIPKq2AUaWRy8IwNKlMqNJflBJu7VYI1XzaaIEaua8xXzqv bmZ8zcbxYvsF9q4LLJdBi9EuGFGvJbSpF9FkUQHYixFrfLtK+m4vml67/EOM2jNjtU20 YaDvCV4+QjfNScWPWwshc8A19xCnvVU9upQPRlp5UmofZ1PaxQPKW6ww01+jIyqpCfux qSYZwNLU5mmmvy/q9OPPNWujaLdGGfw/RpnhEmZOKBGUn/lEBB6q0n5Hde8Xc62t6zE5 5K1A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date; bh=yqKaVHBwD3P5KNO+JV43iFleGVoTdaDnvO1Yqf4vQmA=; b=i5jTlP3jEz1PSUkHIgtOe5Tqce0SCg3ouYyAmZDg4XSgdJkOf2sj90n1Bv59iHVi4z sPKaLvaBH+wrROdS96Z7oAdaLTLh4+CHQJ3WngBzerDLtm6sHfL9S0kxSaqNt9Ict3s+ NEqqG9szG8lJZwthG6EjfsvgDTT7VyCbX+D+yFqysGCjVkOYJVui0ZyLo8tDunON3693 ldZSBPYpAc378NcbfDUsjKTACkXy39Q/ZYd9dK0Q7Cln3T5MVN3p+d5rD8BrVNXGnRQf RL4lZAsTMgXik7QnO4hYtDoaunr3T3w0pEmyRg0Hk1z50fhOxubPvrek+9dw4Yj4s0LW /LYA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of jack@suse.cz designates 195.135.220.15 as permitted sender) smtp.mailfrom=jack@suse.cz Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id l1si543754edi.296.2019.03.13.02.58.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Mar 2019 02:58:35 -0700 (PDT) Received-SPF: pass (google.com: domain of jack@suse.cz designates 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jack@suse.cz designates 195.135.220.15 as permitted sender) smtp.mailfrom=jack@suse.cz X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 148B8AF42; Wed, 13 Mar 2019 09:58:35 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 5C8701E3FE8; Wed, 13 Mar 2019 10:58:34 +0100 (CET) Date: Wed, 13 Mar 2019 10:58:34 +0100 From: Jan Kara To: "Aneesh Kumar K.V" Cc: dan.j.williams@intel.com, Ross Zwisler , Jan Kara , akpm@linux-foundation.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, Alexander Viro Subject: Re: [PATCH v2] fs/dax: deposit pagetable even when installing zero page Message-ID: <20190313095834.GF32521@quack2.suse.cz> References: <20190309120721.21416-1-aneesh.kumar@linux.ibm.com> <8736nrnzxm.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8736nrnzxm.fsf@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 13-03-19 10:17:17, Aneesh Kumar K.V wrote: > > Hi Dan/Andrew/Jan, > > "Aneesh Kumar K.V" writes: > > > Architectures like ppc64 use the deposited page table to store hardware > > page table slot information. Make sure we deposit a page table when > > using zero page at the pmd level for hash. > > > > Without this we hit > > > > Unable to handle kernel paging request for data at address 0x00000000 > > Faulting instruction address: 0xc000000000082a74 > > Oops: Kernel access of bad area, sig: 11 [#1] > > .... > > > > NIP [c000000000082a74] __hash_page_thp+0x224/0x5b0 > > LR [c0000000000829a4] __hash_page_thp+0x154/0x5b0 > > Call Trace: > > hash_page_mm+0x43c/0x740 > > do_hash_page+0x2c/0x3c > > copy_from_iter_flushcache+0xa4/0x4a0 > > pmem_copy_from_iter+0x2c/0x50 [nd_pmem] > > dax_copy_from_iter+0x40/0x70 > > dax_iomap_actor+0x134/0x360 > > iomap_apply+0xfc/0x1b0 > > dax_iomap_rw+0xac/0x130 > > ext4_file_write_iter+0x254/0x460 [ext4] > > __vfs_write+0x120/0x1e0 > > vfs_write+0xd8/0x220 > > SyS_write+0x6c/0x110 > > system_call+0x3c/0x130 > > > > Fixes: b5beae5e224f ("powerpc/pseries: Add driver for PAPR SCM regions") > > Reviewed-by: Jan Kara > > Signed-off-by: Aneesh Kumar K.V > > Any suggestion on which tree this patch should got to? Also since this > fix a kernel crash, we may want to get this to 5.1? I think this should go through Dan's tree... Honza > > --- > > Changes from v1: > > * Add reviewed-by: > > * Add Fixes: > > > > fs/dax.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/fs/dax.c b/fs/dax.c > > index 6959837cc465..01bfb2ac34f9 100644 > > --- a/fs/dax.c > > +++ b/fs/dax.c > > @@ -33,6 +33,7 @@ > > #include > > #include > > #include > > +#include > > #include "internal.h" > > > > #define CREATE_TRACE_POINTS > > @@ -1410,7 +1411,9 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, > > { > > struct address_space *mapping = vmf->vma->vm_file->f_mapping; > > unsigned long pmd_addr = vmf->address & PMD_MASK; > > + struct vm_area_struct *vma = vmf->vma; > > struct inode *inode = mapping->host; > > + pgtable_t pgtable = NULL; > > struct page *zero_page; > > spinlock_t *ptl; > > pmd_t pmd_entry; > > @@ -1425,12 +1428,22 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, > > *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, > > DAX_PMD | DAX_ZERO_PAGE, false); > > > > + if (arch_needs_pgtable_deposit()) { > > + pgtable = pte_alloc_one(vma->vm_mm); > > + if (!pgtable) > > + return VM_FAULT_OOM; > > + } > > + > > ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); > > if (!pmd_none(*(vmf->pmd))) { > > spin_unlock(ptl); > > goto fallback; > > } > > > > + if (pgtable) { > > + pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); > > + mm_inc_nr_ptes(vma->vm_mm); > > + } > > pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); > > pmd_entry = pmd_mkhuge(pmd_entry); > > set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); > > @@ -1439,6 +1452,8 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, > > return VM_FAULT_NOPAGE; > > > > fallback: > > + if (pgtable) > > + pte_free(vma->vm_mm, pgtable); > > trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry); > > return VM_FAULT_FALLBACK; > > } > > -- > > 2.20.1 > > -aneesh > -- Jan Kara SUSE Labs, CR