From nobody Tue Apr 7 10:39:53 2026 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 90E72ECAAD4 for ; Mon, 29 Aug 2022 21:27:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229967AbiH2V1g (ORCPT ); Mon, 29 Aug 2022 17:27:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229956AbiH2V0u (ORCPT ); Mon, 29 Aug 2022 17:26:50 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39CAE9E888 for ; Mon, 29 Aug 2022 14:26:15 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id i25-20020a635859000000b0042bbb74be8bso2624710pgm.5 for ; Mon, 29 Aug 2022 14:26:14 -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; bh=K93TFWAb7JwQdWCvuFbBF/NwLgqzppA/TxAstG/QPvU=; b=f8ZHy6CiTcDXROb3pFMLfetBSV+kFVTeZws7OjDiiohYptMrJjGynWZ4jN+J/j3SJj dCEDPAmPkmnX5B3X46hqeY2mb8ZvMpLB7j64gw3uDHSYMAUM2B6ucp8KKPug6MxLnEu7 BmebG6DC6czjsVXnb7ENc9u7p9QGYJElvc7qRNsIMqXvgjewnR2ulhT9EyPiZ2zz1B9D 56/cpf1MfCjBxFK5vFsjvAIH2zjjfVoYxcmJWgmvbc3eCKVdp1qhJM+tuigQjNUJJMgZ jrHBPRDF7lp+rxYzH8zskIPXprMRBcWxeh9qo4POOeyeUnThUPILDVIwum49CxVeKLEs T9zA== 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; bh=K93TFWAb7JwQdWCvuFbBF/NwLgqzppA/TxAstG/QPvU=; b=yguYos31KDmZgoOyO8nJfP16xaXx0z1lgP88ijLpXJHVPgTHRit6rUC0gMN0a1GM9/ Pk63QZUh48bjR1BMHvO5DliukMhHp+CHpr9N2hlxv9RVqDoPeTUilVRcp70yG+26CBf9 7i4atw6V8nGbhNOrcQwnFy02upV3gv/Gu/ArIdacVcp8pP09TKoedJuUew1au7AHY2ZA C6r/YHlM6Nh0IEMLRCROJZUM8D9+NdEYprL5f6WFoxyRvC2j0ATpZsVxOT7s3IMLmWcI 56ixFtTHqhm0kX2MunIhKf2SbzqdxhIpkpyxBZpJlBRei7y6PQ190fhadaXwgxHleXhK Hhsg== X-Gm-Message-State: ACgBeo0okVUtIzeeQKkMM2cxSjbQ+s3Y5jzsZV/Xc3cF4GZeYocaP+uv 6QMc8/SvUZz737/Bq1M3OqQVhnwEdN4= X-Google-Smtp-Source: AA6agR7nf9+ItGZZ0+7hqrcNY7xNhTop6ny3nOph/OxIOFh5WmAm4Kp1l2Jp+ca/L6EEvcmkimt0snMwAs0= X-Received: from surenb-spec.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3e30]) (user=surenb job=sendgmr) by 2002:a17:902:b094:b0:173:12d1:4ece with SMTP id p20-20020a170902b09400b0017312d14ecemr18383730plr.117.1661808370030; Mon, 29 Aug 2022 14:26:10 -0700 (PDT) Date: Mon, 29 Aug 2022 21:25:22 +0000 In-Reply-To: <20220829212531.3184856-1-surenb@google.com> Mime-Version: 1.0 References: <20220829212531.3184856-1-surenb@google.com> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Message-ID: <20220829212531.3184856-20-surenb@google.com> Subject: [RFC PATCH 19/28] mm: disallow do_swap_page to handle page faults under VMA lock 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, laurent.dufour@fr.ibm.com, paulmck@kernel.org, riel@surriel.com, 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, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, surenb@google.com, kernel-team@android.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Due to the possibility of do_swap_page dropping mmap_lock, abort fault handling under VMA lock and retry holding mmap_lock. This can be handled more gracefully in the future. Signed-off-by: Suren Baghdasaryan --- mm/memory.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index 9ac9944e8c62..29d2f49f922a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3738,6 +3738,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) vm_fault_t ret =3D 0; void *shadow =3D NULL; =20 + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + ret =3D VM_FAULT_RETRY; + goto out; + } + if (!pte_unmap_same(vmf)) goto out; =20 --=20 2.37.2.672.g94769d06f0-goog