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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 20C42ECAAD1 for ; Thu, 1 Sep 2022 17:42:52 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4MJT0B3W9Pz3fP8 for ; Fri, 2 Sep 2022 03:42:50 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20210112 header.b=RqTxEDKm; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=flex--surenb.bounces.google.com (client-ip=2607:f8b0:4864:20::114a; helo=mail-yw1-x114a.google.com; envelope-from=3du0qywykdlmlnkxguzhhzex.vhfebgnqiiv-wxoeblml.hsetul.hkz@flex--surenb.bounces.google.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20210112 header.b=RqTxEDKm; dkim-atps=neutral Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4MJSr93l5Yz3bnj for ; Fri, 2 Sep 2022 03:35:52 +1000 (AEST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-343a77f2129so37855687b3.15 for ; Thu, 01 Sep 2022 10:35:52 -0700 (PDT) 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; bh=IUrOZBQLzZPUHaSf75EcaCRmzwc/1Uln8Bhr3CCRW40=; b=RqTxEDKmKz8lQ9e4qoEc4uYxV2l6ZaYMJyNDEM2PccdKcjIk6CnRCwBsEF2cj3JFvG j1vM9+I5MFJ8Y28kW9pfnzwXL/sLYGBlEyABKHcApM/RmMkSzapOCNpQMv7qth5lMe9Z r4q/GOZemPIxyE1pZ9TWp0QmyjLs2nHHEkPOAyS+5ktrUUhx4EO8hL8MjHB9ieBIjUIm Yg7XSf+rAL+v2NSP5NDXERvFs20Phv4/bhur7fMLyFA6L2AN5XBQFKbc4pQ3AuRWkJ+n hhBQmROSc08GaGFWWbM/WsNha74+z1T1INvujKYoiSdnjlDI7QzZLxl1fThOa82IPdUF 4lpQ== 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; bh=IUrOZBQLzZPUHaSf75EcaCRmzwc/1Uln8Bhr3CCRW40=; b=DC8R5B0bfLXdSR4pNppT9qGafxzkyKBwBDDnyAoX4o/3ThFcMfOrAm2yQUjrxLPxGo xpWFbrewjXOnKkcRNJn/VFquSoilPB9OxxtNYBENdMPb0p7jcpZvauYF8qYHbJSGARZQ FuplsqQK7/WXC3V97Bc8mR+fch5AMF1sT7XaBFqWgEzWEIF4e5Ncapzt+GQWHo8EETz/ DSZxHh5hgMAWQwVJ5odDOjq3esdOGivClr70an2DBinPglyGnxT/QbOC1aFo5tf7y4Yz 6uIyGEY46Mqw+mbOEOcBJnzTo8JKhUeOPZfazYlTSO7mgKfDy3yWHno8Sc97AocgCW/x 1S3g== X-Gm-Message-State: ACgBeo1S8d4n7qdOeoarMK/nFNzMOM5JjVNIpWm1yYU6yhHafjy0LZV8 BrgG5voGBgirjqVjNPfmoFIr+4v/Ftk= X-Google-Smtp-Source: AA6agR7hyHeb8khg+/3ZoJp3oFVauMFyBSatbGnIGl1CpSfGDYZylUwLzf/LZXvggze+7Aght5uln8kJbB0= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:1bfc:e7ee:6530:4449]) (user=surenb job=sendgmr) by 2002:a0d:e083:0:b0:343:2928:867f with SMTP id j125-20020a0de083000000b003432928867fmr6902464ywe.467.1662053750534; Thu, 01 Sep 2022 10:35:50 -0700 (PDT) Date: Thu, 1 Sep 2022 10:34:59 -0700 In-Reply-To: <20220901173516.702122-1-surenb@google.com> Mime-Version: 1.0 References: <20220901173516.702122-1-surenb@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220901173516.702122-12-surenb@google.com> Subject: [RFC PATCH RESEND 11/28] mm/mmap: mark VMAs as locked before merging or splitting them From: Suren Baghdasaryan To: akpm@linux-foundation.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: michel@lespinasse.org, joelaf@google.com, songliubraving@fb.com, mhocko@suse.com, david@redhat.com, peterz@infradead.org, bigeasy@linutronix.de, peterx@redhat.com, dhowells@redhat.com, linux-mm@kvack.org, jglisse@google.com, dave@stgolabs.net, minchan@google.com, x86@kernel.org, hughd@google.com, willy@infradead.org, laurent.dufour@fr.ibm.com, mgorman@suse.de, rientjes@google.com, axelrasmussen@google.com, kernel-team@android.com, paulmck@kernel.org, liam.howlett@oracle.com, luto@kernel.org, ldufour@linux.ibm.com, surenb@google.com, vbabka@suse.cz, linux-arm-kernel@lists.infradead.org, kent.overstreet@linux.dev, linux-kernel@vger.kernel.org, hannes@cmpxchg.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Decisions about whether VMAs can be merged or split must be made while VMAs are protected from the changes which can affect that decision. For example, merge_vma uses vma->anon_vma in its decision whether the VMA can be merged. Meanwhile, page fault handler changes vma->anon_vma during COW operation. Mark all VMAs which might be affected by a merge or split operation as locked before making decision how such operations should be performed. Signed-off-by: Suren Baghdasaryan --- mm/mmap.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/mm/mmap.c b/mm/mmap.c index ed58cf0689b2..ade3909c89b4 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1147,10 +1147,17 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm, if (vm_flags & VM_SPECIAL) return NULL; + if (prev) + vma_mark_locked(prev); next = vma_next(mm, prev); area = next; - if (area && area->vm_end == end) /* cases 6, 7, 8 */ + if (area) + vma_mark_locked(area); + if (area && area->vm_end == end) { /* cases 6, 7, 8 */ next = next->vm_next; + if (next) + vma_mark_locked(next); + } /* verify some invariant that must be enforced by the caller */ VM_WARN_ON(prev && addr <= prev->vm_start); @@ -2687,6 +2694,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *new; int err; + vma_mark_locked(vma); if (vma->vm_ops && vma->vm_ops->may_split) { err = vma->vm_ops->may_split(vma, addr); if (err) -- 2.37.2.789.g6183377224-goog