From nobody Tue Apr 7 10:38:50 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 D280EECAAD4 for ; Mon, 29 Aug 2022 21:27:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229863AbiH2V1O (ORCPT ); Mon, 29 Aug 2022 17:27:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229940AbiH2V0n (ORCPT ); Mon, 29 Aug 2022 17:26:43 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A19F9E891 for ; Mon, 29 Aug 2022 14:26:15 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id q9-20020a17090aa00900b001fd93514a68so4327603pjp.3 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=+ZeFgC+onLi5H2Gk/r+wfB2lUIAEpTgiMaISz2j8Yh8=; b=sfdQ+2NyYwxA7WE4W+U26tjnRsGpTwH+W4yCMsULIhDPYOMjHM3COZzPg/S6KTqrLL mCgPnd6W8rrgwvL37XiGeYHG8ArgrFQG0UGf2gLsolv/ME8hJmTyRg7Fg1LBPlsPaNI3 te4whtYEHF8c2GeRvQHa/rDrJjk62KSTUlVEPYqGvjKgQGKn8f4Dp8C4KiASRefP1Qh1 bQmVBjd8KI32N8+vGT1M5VRcf57cOjajmNaLyJUUpin1ccvlQLSGjkUAJOTaDxWOJrJ5 Pk3cN7LOZgsgUwKnowGjucplCuekHbu//K343iXFhb3F2AjszKhuURdvTUr7Fsy7vLjJ fKug== 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=+ZeFgC+onLi5H2Gk/r+wfB2lUIAEpTgiMaISz2j8Yh8=; b=0WhHNp+Psn1uZcM7tnssYkTXQuKK03hKUOCjWoI3BEFXnigAtIVartwiKm+ZzS8BjU OjUl/sN13/ZIO7hL/OXNN3+peDvajdpysxrfaB8juq0pTADEHWFNEtxjs51KWkMFvhl4 YjgCMMyuTG4PodFxqcqBdEhjzHZJztpsp3ulp7PJkfQU9OIsgoMqegwIVy91V59fVfO9 r/tlpOe/CrvuanRmqML8+qT/YEvgDihwJs0GO3ZZRshToxT5aMtQpEi60hFb9Ho9HXzm AxF5D8JUpNORXF19ChKDyXf4Svo6RQFZNQnpki2WKEkC+IsQLJfXXYaUoxt5Xh744B4N ivfQ== X-Gm-Message-State: ACgBeo3xUpGG5Do3ibkTCxHCYw70BGUOuACDkVIbsmIxlA4A05uFT5ip 2GBFo17U4aoFElorfMw5A3CnCfvFz6o= X-Google-Smtp-Source: AA6agR60gqv1XJF9S7yhKpnItHkmCdUjQh3CpTVXyWE3xiDHKhNiTBjmbY9F8YGX1B9vpUO9txTmTcIisVc= X-Received: from surenb-spec.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:3e30]) (user=surenb job=sendgmr) by 2002:a17:902:6b88:b0:173:c1:691b with SMTP id p8-20020a1709026b8800b0017300c1691bmr18372367plk.18.1661808366708; Mon, 29 Aug 2022 14:26:06 -0700 (PDT) Date: Mon, 29 Aug 2022 21:25:20 +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: <20220829212531.3184856-18-surenb@google.com> Subject: [RFC PATCH 17/28] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration 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" Pagefault handlers might need to fire MMU notifications while a new notifier is being registered. Modify mm_take_all_locks to mark all VMAs as locked and prevent this race with fault handlers that would hold VMA locks. Signed-off-by: Suren Baghdasaryan --- mm/mmap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index b31cc97c2803..1edfcd384f5e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3538,6 +3538,7 @@ static void vm_lock_mapping(struct mm_struct *mm, str= uct address_space *mapping) * hugetlb mapping); * - all i_mmap_rwsem locks; * - all anon_vma->rwseml + * - all vmas marked locked * * We can take all locks within these types randomly because the VM code * doesn't nest them and we protected from parallel mm_take_all_locks() by @@ -3579,6 +3580,7 @@ int mm_take_all_locks(struct mm_struct *mm) if (vma->anon_vma) list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) vm_lock_anon_vma(mm, avc->anon_vma); + vma_mark_locked(vma); } =20 return 0; @@ -3636,6 +3638,7 @@ void mm_drop_all_locks(struct mm_struct *mm) mmap_assert_write_locked(mm); BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); =20 + vma_mark_unlocked_all(mm); for (vma =3D mm->mmap; vma; vma =3D vma->vm_next) { if (vma->anon_vma) list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) --=20 2.37.2.672.g94769d06f0-goog