From patchwork Tue May 25 08:33:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 12278163 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=-13.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY, USER_AGENT_GIT 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 C38A6C2B9F8 for ; Tue, 25 May 2021 08:34:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6D92761401 for ; Tue, 25 May 2021 08:34:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D92761401 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5F7E28E0001; Tue, 25 May 2021 04:34:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 561EA6B0070; Tue, 25 May 2021 04:34:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E96DD8E0001; Tue, 25 May 2021 04:34:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0134.hostedemail.com [216.40.44.134]) by kanga.kvack.org (Postfix) with ESMTP id A5C226B006E for ; Tue, 25 May 2021 04:34:23 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4B54081FC for ; Tue, 25 May 2021 08:34:23 +0000 (UTC) X-FDA: 78179091606.15.503F35B Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by imf09.hostedemail.com (Postfix) with ESMTP id 1CB666000261 for ; Tue, 25 May 2021 08:34:18 +0000 (UTC) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 14P8Y4tV046089; Tue, 25 May 2021 04:34:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=1CZV2oWhvddTbDHFXWMDZlBJJyfSVlv//BAQO+GCgpg=; b=VY7P6lcf8lWW4QUlDSHr90ygWLpggMrCSTG+acJBY3rHMcOlKqZ52QYDr7JJOe994K79 RmlG46qGsGeaetfTX23og3xXdiHVsN+7HgcBRGgRLzY4gE+8P5OsUEyCnQV3cz2ZEfGi IxqQM+8WIwijGJNUHPILmjVRSvy5wlh4HLlzQ3tmVEBHUGCQzxT5Lq6w+C3cx01FiqZA ynJKP/eAbb+vTuArKGuIgrIDxutF628uZMDkIOsb1LC7n5hCQ+posyZUCo3VgTPdR14S +fRo0TD4q+IE0EJQVbrMiMR0bYLl4cBnQ7KTwHq/sCKrsE5lwYSNN/sIC9yoxrn6IUyz Hg== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 38rw7gh6jx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 25 May 2021 04:34:09 -0400 Received: from m0098396.ppops.net (m0098396.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 14P8Y4kU046154; Tue, 25 May 2021 04:34:08 -0400 Received: from ppma03dal.us.ibm.com (b.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.11]) by mx0a-001b2d01.pphosted.com with ESMTP id 38rw7gh6j6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 25 May 2021 04:34:08 -0400 Received: from pps.filterd (ppma03dal.us.ibm.com [127.0.0.1]) by ppma03dal.us.ibm.com (8.16.0.43/8.16.0.43) with SMTP id 14P8S0W9025797; Tue, 25 May 2021 08:34:07 GMT Received: from b03cxnp07027.gho.boulder.ibm.com (b03cxnp07027.gho.boulder.ibm.com [9.17.130.14]) by ppma03dal.us.ibm.com with ESMTP id 38psk92se2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 25 May 2021 08:34:07 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp07027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 14P8Y6aF27787632 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 May 2021 08:34:06 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5AAFDC6061; Tue, 25 May 2021 08:34:06 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8CF95C605F; Tue, 25 May 2021 08:34:02 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.85.69.234]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 25 May 2021 08:34:02 +0000 (GMT) From: "Aneesh Kumar K.V" To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, kaleshsingh@google.com, npiggin@gmail.com, joel@joelfernandes.org, Christophe Leroy , Linus Torvalds , "Kirill A . Shutemov" , "Aneesh Kumar K.V" Subject: [RFC PATCH 1/2] mm/mremap: Fix race between MOVE_PMD mremap and pageout Date: Tue, 25 May 2021 14:03:43 +0530 Message-Id: <20210525083344.162377-1-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.31.1 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: hd65BHOSNHL-jGQwKAQEJn50Epj6OaHU X-Proofpoint-ORIG-GUID: MTyE2jYdDIuMha-iy4z4wfXD8Av98DWD X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-05-25_05:2021-05-24,2021-05-25 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 lowpriorityscore=0 spamscore=0 clxscore=1011 adultscore=0 mlxlogscore=999 mlxscore=0 phishscore=0 priorityscore=1501 bulkscore=0 suspectscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105250059 X-Rspamd-Queue-Id: 1CB666000261 Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=VY7P6lcf; dmarc=pass (policy=none) header.from=ibm.com; spf=pass (imf09.hostedemail.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=aneesh.kumar@linux.ibm.com X-Rspamd-Server: rspam03 X-Stat-Signature: j8poiqjdacnke46nf6f78hsww636ejxb X-HE-Tag: 1621931658-372482 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: CPU 1 CPU 2 CPU 3 mremap(old_addr, new_addr) page_shrinker/try_to_unmap_one mmap_write_lock_killable() addr = old_addr lock(pte_ptl) lock(pmd_ptl) pmd = *old_pmd pmd_clear(old_pmd) flush_tlb_range(old_addr) *new_pmd = pmd *new_addr = 10; and fills TLB with new addr and old pfn unlock(pmd_ptl) ptep_clear_flush() old pfn is free. Stale TLB entry Fix this race by holding pmd lock in pageout. This still doesn't handle the race between MOVE_PUD and pageout. Fixes: 2c91bd4a4e2e ("mm: speed up mremap by 20x on large regions") Link: https://lore.kernel.org/linux-mm/CAHk-=wgXVR04eBNtxQfevontWnP6FDm+oj5vauQXP3S-huwbPw@mail.gmail.com Signed-off-by: Aneesh Kumar K.V --- include/linux/rmap.h | 9 ++++++--- mm/page_vma_mapped.c | 36 ++++++++++++++++++------------------ 2 files changed, 24 insertions(+), 21 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index def5c62c93b3..272ab0c2b60b 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -207,7 +207,8 @@ struct page_vma_mapped_walk { unsigned long address; pmd_t *pmd; pte_t *pte; - spinlock_t *ptl; + spinlock_t *pte_ptl; + spinlock_t *pmd_ptl; unsigned int flags; }; @@ -216,8 +217,10 @@ static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw) /* HugeTLB pte is set to the relevant page table entry without pte_mapped. */ if (pvmw->pte && !PageHuge(pvmw->page)) pte_unmap(pvmw->pte); - if (pvmw->ptl) - spin_unlock(pvmw->ptl); + if (pvmw->pte_ptl) + spin_unlock(pvmw->pte_ptl); + if (pvmw->pmd_ptl) + spin_unlock(pvmw->pmd_ptl); } bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw); diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 2cf01d933f13..87a2c94c7e27 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -47,8 +47,10 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw) return false; } } - pvmw->ptl = pte_lockptr(pvmw->vma->vm_mm, pvmw->pmd); - spin_lock(pvmw->ptl); + if (USE_SPLIT_PTE_PTLOCKS) { + pvmw->pte_ptl = pte_lockptr(pvmw->vma->vm_mm, pvmw->pmd); + spin_lock(pvmw->pte_ptl); + } return true; } @@ -162,8 +164,8 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) if (!pvmw->pte) return false; - pvmw->ptl = huge_pte_lockptr(page_hstate(page), mm, pvmw->pte); - spin_lock(pvmw->ptl); + pvmw->pte_ptl = huge_pte_lockptr(page_hstate(page), mm, pvmw->pte); + spin_lock(pvmw->pte_ptl); if (!check_pte(pvmw)) return not_found(pvmw); return true; @@ -179,6 +181,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) if (!pud_present(*pud)) return false; pvmw->pmd = pmd_offset(pud, pvmw->address); + pvmw->pmd_ptl = pmd_lock(mm, pvmw->pmd); /* * Make sure the pmd value isn't cached in a register by the * compiler and used as a stale value after we've observed a @@ -186,7 +189,6 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) */ pmde = READ_ONCE(*pvmw->pmd); if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) { - pvmw->ptl = pmd_lock(mm, pvmw->pmd); if (likely(pmd_trans_huge(*pvmw->pmd))) { if (pvmw->flags & PVMW_MIGRATION) return not_found(pvmw); @@ -206,14 +208,10 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) } } return not_found(pvmw); - } else { - /* THP pmd was split under us: handle on pte level */ - spin_unlock(pvmw->ptl); - pvmw->ptl = NULL; } - } else if (!pmd_present(pmde)) { - return false; - } + } else if (!pmd_present(pmde)) + return not_found(pvmw); + if (!map_pte(pvmw)) goto next_pte; while (1) { @@ -233,19 +231,21 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) /* Did we cross page table boundary? */ if (pvmw->address % PMD_SIZE == 0) { pte_unmap(pvmw->pte); - if (pvmw->ptl) { - spin_unlock(pvmw->ptl); - pvmw->ptl = NULL; + if (pvmw->pte_ptl) { + spin_unlock(pvmw->pte_ptl); + pvmw->pte_ptl = NULL; } + spin_unlock(pvmw->pmd_ptl); + pvmw->pmd_ptl = NULL; goto restart; } else { pvmw->pte++; } } while (pte_none(*pvmw->pte)); - if (!pvmw->ptl) { - pvmw->ptl = pte_lockptr(mm, pvmw->pmd); - spin_lock(pvmw->ptl); + if (USE_SPLIT_PTE_PTLOCKS && !pvmw->pte_ptl) { + pvmw->pte_ptl = pte_lockptr(mm, pvmw->pmd); + spin_lock(pvmw->pte_ptl); } } } From patchwork Tue May 25 08:33:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 12278165 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 54306C47084 for ; Tue, 25 May 2021 08:34:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D3D6861419 for ; Tue, 25 May 2021 08:34:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D3D6861419 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0A9306B006E; Tue, 25 May 2021 04:34:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B32378E0002; Tue, 25 May 2021 04:34:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 194E66B0071; Tue, 25 May 2021 04:34:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0097.hostedemail.com [216.40.44.97]) by kanga.kvack.org (Postfix) with ESMTP id C4C826B0070 for ; Tue, 25 May 2021 04:34:23 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 666898249980 for ; Tue, 25 May 2021 08:34:23 +0000 (UTC) X-FDA: 78179091606.08.3EB6EDD Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by imf12.hostedemail.com (Postfix) with ESMTP id B23EB2C8 for ; Tue, 25 May 2021 08:34:14 +0000 (UTC) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 14P8WbjP154216; Tue, 25 May 2021 04:34:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=AfxNOjqF9LJeSahmaxMJCGW9X/G+3N1LoF4lN/GbI/Y=; b=TJHY1eM1nxdfHgIwqTE2wZufg8mCmoVJj4HcZlAKfowY2Kor9++RtF9ZwVvcS3RUjS7T ztrUXHSHcROrUQ1D9c874icRv8ov6mD2k828Vvv66c/aPKXygIRlszkxsq6hP2XJhSG4 Z/30A5RqBZZNIfZr3EInXHZxXp8IbkdgmZQ2a3dHTmAclNPndJxvm8ugTwY6eszJ1iA7 ffw2N1hRw/HMYCV7Iq8BSjFh9F1z8l1qfZQ4BzovUJkETjv5p9UbN4gotXGKH4nyVla9 7KvxMhAwoF8xj5cyk+hNjL0oNwMXCEQn5WUkDlkD8KnaI//sQ1X/tpGnq8hPmizGL5wB 6g== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 38ruf44d91-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 25 May 2021 04:34:13 -0400 Received: from m0098399.ppops.net (m0098399.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 14P8Wb1W154223; Tue, 25 May 2021 04:34:13 -0400 Received: from ppma04wdc.us.ibm.com (1a.90.2fa9.ip4.static.sl-reverse.com [169.47.144.26]) by mx0a-001b2d01.pphosted.com with ESMTP id 38ruf44d7r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 25 May 2021 04:34:12 -0400 Received: from pps.filterd (ppma04wdc.us.ibm.com [127.0.0.1]) by ppma04wdc.us.ibm.com (8.16.0.43/8.16.0.43) with SMTP id 14P8RIqW016162; Tue, 25 May 2021 08:34:11 GMT Received: from b03cxnp07028.gho.boulder.ibm.com (b03cxnp07028.gho.boulder.ibm.com [9.17.130.15]) by ppma04wdc.us.ibm.com with ESMTP id 38psk9de4a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 25 May 2021 08:34:11 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 14P8YA7729032806 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 May 2021 08:34:10 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B0E5AC6059; Tue, 25 May 2021 08:34:10 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D62C9C605B; Tue, 25 May 2021 08:34:06 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.85.69.234]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 25 May 2021 08:34:06 +0000 (GMT) From: "Aneesh Kumar K.V" To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, kaleshsingh@google.com, npiggin@gmail.com, joel@joelfernandes.org, Christophe Leroy , Linus Torvalds , "Kirill A . Shutemov" , "Aneesh Kumar K.V" Subject: [RFC PATCH 2/2] mm/mremap: Fix race between MOVE_PUD mremap and pageout Date: Tue, 25 May 2021 14:03:44 +0530 Message-Id: <20210525083344.162377-2-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210525083344.162377-1-aneesh.kumar@linux.ibm.com> References: <20210525083344.162377-1-aneesh.kumar@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: L4DAVE5xOk4BA6qopkTE-hS6-YRF3qPP X-Proofpoint-ORIG-GUID: 96zbzpYr0N72PPDMETh8ZQX6uygMgBZF X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-05-25_05:2021-05-24,2021-05-25 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 mlxscore=0 bulkscore=0 malwarescore=0 suspectscore=0 mlxlogscore=999 spamscore=0 impostorscore=0 phishscore=0 lowpriorityscore=0 priorityscore=1501 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2105250059 X-Rspamd-Queue-Id: B23EB2C8 Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=ibm.com header.s=pp1 header.b=TJHY1eM1; spf=pass (imf12.hostedemail.com: domain of aneesh.kumar@linux.ibm.com designates 148.163.156.1 as permitted sender) smtp.mailfrom=aneesh.kumar@linux.ibm.com; dmarc=pass (policy=none) header.from=ibm.com X-Rspamd-Server: rspam04 X-Stat-Signature: rypw5jeafe8zp4qxndp3frw3bsggwjoh X-HE-Tag: 1621931654-442072 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: CPU 1 CPU 2 CPU 3 mremap(old_addr, new_addr) page_shrinker/try_to_unmap_one mmap_write_lock_killable() addr = old_addr lock(pte_ptl) lock(pud_ptl) pud = *old_pud pud_clear(old_pud) flush_tlb_range(old_addr) *new_pud = pud *new_addr = 10; and fills TLB with new addr and old pfn unlock(pud_ptl) ptep_clear_flush() old pfn is free. Stale TLB entry Fix this race by holding pud lock in pageout. Signed-off-by: Aneesh Kumar K.V --- include/linux/rmap.h | 4 ++++ mm/page_vma_mapped.c | 13 ++++++++++--- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 272ab0c2b60b..491c65ce1d46 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -209,6 +209,7 @@ struct page_vma_mapped_walk { pte_t *pte; spinlock_t *pte_ptl; spinlock_t *pmd_ptl; + spinlock_t *pud_ptl; unsigned int flags; }; @@ -221,6 +222,9 @@ static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw) spin_unlock(pvmw->pte_ptl); if (pvmw->pmd_ptl) spin_unlock(pvmw->pmd_ptl); + if (pvmw->pud_ptl) + spin_unlock(pvmw->pud_ptl); + } bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw); diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 87a2c94c7e27..c913bc34b1d3 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -180,8 +180,11 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) pud = pud_offset(p4d, pvmw->address); if (!pud_present(*pud)) return false; + + pvmw->pud_ptl = pud_lock(mm, pud); pvmw->pmd = pmd_offset(pud, pvmw->address); - pvmw->pmd_ptl = pmd_lock(mm, pvmw->pmd); + if (USE_SPLIT_PMD_PTLOCKS) + pvmw->pmd_ptl = pmd_lock(mm, pvmw->pmd); /* * Make sure the pmd value isn't cached in a register by the * compiler and used as a stale value after we've observed a @@ -235,8 +238,12 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) spin_unlock(pvmw->pte_ptl); pvmw->pte_ptl = NULL; } - spin_unlock(pvmw->pmd_ptl); - pvmw->pmd_ptl = NULL; + if (pvmw->pmd_ptl) { + spin_unlock(pvmw->pmd_ptl); + pvmw->pmd_ptl = NULL; + } + spin_unlock(pvmw->pud_ptl); + pvmw->pud_ptl = NULL; goto restart; } else { pvmw->pte++;