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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEBD7C636CC for ; Thu, 16 Feb 2023 05:20:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229804AbjBPFUE (ORCPT ); Thu, 16 Feb 2023 00:20:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229746AbjBPFTT (ORCPT ); Thu, 16 Feb 2023 00:19:19 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B97D742BD8 for ; Wed, 15 Feb 2023 21:18:45 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id p7-20020a257407000000b0091b90b20cd9so869939ybc.6 for ; Wed, 15 Feb 2023 21:18:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Gs5XDlSmqlz144wCEPg25vfe9kudkVyQE95J1Pewv8Q=; b=NZSRPVmVQg07iGqxuaNSoyEyX/JUlE5074LqD7StZA8wPOZx80SXxNMt5E5KxxrtoC 5GmbXen1kftSSNBaHdmndb327iEU+JgvGlsjv+jrut0kw6bBF6uNimcKzz4dFOSEItYW Y4LEl4ERFvkTfh+pRssZBSprx0WHPyqr3iZkWvDeufJqDlNo5Dl9o53Xv9skjZ4WRCg9 pPw2zfwLYTP83BBCg7T3fM4u8tR26MmRDA1XMM3A/clmWDV/BI6rgpWB66aseND2aMHJ sak6MgPcdV5XEwJQs9ETMkutqiCQEhW6TAM4KAr4SAjK7KgYItsJ/rcb5RNyZGDs+f6q Q5lA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Gs5XDlSmqlz144wCEPg25vfe9kudkVyQE95J1Pewv8Q=; b=z5HT4SprMcPNuNcT3lm4djTjfO3QyMjxUIKUeVcycvYqZ9+Yhz5oyJyKR93sl/bIxJ hZbvWKKE1WpGQuDnImLs2vScmX/viRzHYfK7MomFeykWIbeTaA92ell6w58ykjrFdsbb +PtuSkGY6Qq3FCWGCygCUsxir5cHEoSxmZ/Xb5SgZOLlvh7QDmt0Qo1lTyJBP3YoGutp RsEadFbhoNPhtJIrUI8BOyVkOCUfMi+NfOcX9d5yS8or9eE3hizsw8TadZ1AB49L+MA4 AGfMwyUBJQpCCweZk2pCiFgRpvizP8sNebKxIP9njMMHKcSoZwqs7myyMyPUNc/OjzLT iCUw== X-Gm-Message-State: AO0yUKWaWg8YbSJgw9u+VRqFYHL33ZJsinlugrWsfA723BW8PENHxxPN /QrRTGxHx7kZy0WEdE26EllXwamHcrw= X-Google-Smtp-Source: AK7set81sG3yc9X92pQzrCT4qIFN1iEujQCfNrT8GtjdXbA2djctnG24/XowjsXx2FP9/9bsOvEUQhAtEC0= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:f781:d5ed:1806:6ebb]) (user=surenb job=sendgmr) by 2002:a81:9345:0:b0:52e:e6ed:30bb with SMTP id k66-20020a819345000000b0052ee6ed30bbmr607996ywg.571.1676524715849; Wed, 15 Feb 2023 21:18:35 -0800 (PST) Date: Wed, 15 Feb 2023 21:17:32 -0800 In-Reply-To: <20230216051750.3125598-1-surenb@google.com> Mime-Version: 1.0 References: <20230216051750.3125598-1-surenb@google.com> X-Mailer: git-send-email 2.39.1.581.gbfd45094c4-goog Message-ID: <20230216051750.3125598-18-surenb@google.com> Subject: [PATCH v3 17/35] mm/mmap: write-lock VMA before shrinking or expanding it From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, chriscli@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, michalechner92@googlemail.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, Suren Baghdasaryan Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vma_expand and vma_shrink change VMA boundaries. Expansion might also result in freeing of an adjacent VMA. Write-lock affected VMAs to prevent concurrent page faults. Signed-off-by: Suren Baghdasaryan --- mm/mmap.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index ec2f8d0af280..f079e5bbcd57 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -674,6 +674,9 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, ret = dup_anon_vma(vma, next); if (ret) return ret; + + /* Lock the VMA before removing it */ + vma_start_write(next); } init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL); @@ -686,6 +689,7 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_iter_prealloc(vmi)) goto nomem; + vma_start_write(vma); vma_adjust_trans_huge(vma, start, end, 0); /* VMA iterator points to previous, so set to start if necessary */ if (vma_iter_addr(vmi) != start) @@ -725,6 +729,7 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, if (vma_iter_prealloc(vmi)) return -ENOMEM; + vma_start_write(vma); init_vma_prep(&vp, vma); vma_adjust_trans_huge(vma, start, end, 0); vma_prepare(&vp); -- 2.39.1