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 X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 AF235C433E1 for ; Sat, 16 May 2020 08:22:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8ECF7206F4 for ; Sat, 16 May 2020 08:22:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kSHTwd5e" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726399AbgEPIWk (ORCPT ); Sat, 16 May 2020 04:22:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725934AbgEPIWj (ORCPT ); Sat, 16 May 2020 04:22:39 -0400 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1F44C061A0C; Sat, 16 May 2020 01:22:39 -0700 (PDT) Received: by mail-pj1-x1044.google.com with SMTP id fu13so2110384pjb.5; Sat, 16 May 2020 01:22:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=n8zeuSyWYmnUTCcGG4KcbVscwA04lg+t/YXhdGOdoRk=; b=kSHTwd5eDGUl/K2MsusgZkFTMR3AophuUBe1kXDJlVfE5ua9O9OGjGOTYBUA3y5LCn 8hfYpuOH9CiRvEIBKKz0DdncM80p7x2LCzSJsHtx9GOPiVNuYor8fBKkYpooLG+K18tI 8c2l3vKaAQh3GcMZwwMvWipE1/aFXrVcw2aOz/ihBV690LmRmrcCqn4JXXF9u7tpAnRQ ymfsLBjAXaAY2/IYj7vPtMnKY5CNAK5wHgJ846IwYx/qZmLwhq4NKXE0mqvPU0LgGQxw YgOazcAPN8DRZkJWwS5Ds8FcdLH04a4/lCqZhFVRLctKTXmMN+hM+6Jb5xlsWjDkNWYd sudg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=n8zeuSyWYmnUTCcGG4KcbVscwA04lg+t/YXhdGOdoRk=; b=ZB79viSLq4sH6E9R2OfAZX+sXv20vMHAhBRN1KEcHy0lqX61n3eaDaT2e8PlP586ic /RQV/Y/P6UShlsgQlFN+Ia2LH05DCTt7pvhorEZEDY+dVljlq0OIni6DLi98G3l6wSFq T70fLxlpnXt9R3EKU3jW0UwZ4X2gqGsMEHbcoZdFOiG9oHOab43Qc+AzlEmNzJhvbyZW GtxEqU1HTEFfDPTA8AXwDK7h1wQe74FtLoJ03UwQDpFwtmeiAOihfXY26VrsX+osLhYB /GgrCy2m3lWMBfdmsEr8A8+SBRGYixP2f4MhfhWqq9Daa05C1CRUezVfS9W3FY6WcbD8 itug== X-Gm-Message-State: AOAM531pT426NTHMwnz7c8aDkkVlqKw35TmUUt/HwKVZtK2KLtzLy2j3 7612Q/Qxo2YMMJ0h+8Vujg== X-Google-Smtp-Source: ABdhPJy0lauqLn17lbGE3w8KJHGHD9NuhDV2LLqXRRaRQTMDJP5PCGFyuaHLhQCh2EmHugUqCHILZg== X-Received: by 2002:a17:90b:1492:: with SMTP id js18mr1459691pjb.212.1589617359233; Sat, 16 May 2020 01:22:39 -0700 (PDT) Received: from localhost.localdomain ([2402:3a80:13a5:a61b:b5d4:b438:1bc1:57f3]) by smtp.gmail.com with ESMTPSA id j7sm3695288pfi.160.2020.05.16.01.22.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 16 May 2020 01:22:38 -0700 (PDT) From: madhuparnabhowmik10@gmail.com To: pbonzini@redhat.com, sean.j.christopherson@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, tglx@linutronix.de, bp@alien8.de Cc: x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, joel@joelfernandes.org, paulmck@kernel.org, frextrite@gmail.com, linux-kernel-mentees@lists.linuxfoundation.org, Madhuparna Bhowmik Subject: [PATCH v2] kvm: Fix false positive RCU usage warning Date: Sat, 16 May 2020 13:52:27 +0530 Message-Id: <20200516082227.22194-1-madhuparnabhowmik10@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Madhuparna Bhowmik Fix the following false positive warnings: [ 9403.765413][T61744] ============================= [ 9403.786541][T61744] WARNING: suspicious RCU usage [ 9403.807865][T61744] 5.7.0-rc1-next-20200417 #4 Tainted: G L [ 9403.838945][T61744] ----------------------------- [ 9403.860099][T61744] arch/x86/kvm/mmu/page_track.c:257 RCU-list traversed in non-reader section!! and [ 9405.859252][T61751] ============================= [ 9405.859258][T61751] WARNING: suspicious RCU usage [ 9405.880867][T61755] ----------------------------- [ 9405.911936][T61751] 5.7.0-rc1-next-20200417 #4 Tainted: G L [ 9405.911942][T61751] ----------------------------- [ 9405.911950][T61751] arch/x86/kvm/mmu/page_track.c:232 RCU-list traversed in non-reader section!! Since srcu read lock is held, these are false positive warnings. Therefore, pass condition srcu_read_lock_held() to list_for_each_entry_rcu(). Reported-by: kernel test robot Signed-off-by: Madhuparna Bhowmik --- v2: -Rebase v5.7-rc5 arch/x86/kvm/mmu/page_track.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index ddc1ec3bdacd..1ad79c7aa05b 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -229,7 +229,8 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new, return; idx = srcu_read_lock(&head->track_srcu); - hlist_for_each_entry_rcu(n, &head->track_notifier_list, node) + hlist_for_each_entry_rcu(n, &head->track_notifier_list, node, + srcu_read_lock_held(&head->track_srcu)) if (n->track_write) n->track_write(vcpu, gpa, new, bytes, n); srcu_read_unlock(&head->track_srcu, idx); @@ -254,7 +255,8 @@ void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot) return; idx = srcu_read_lock(&head->track_srcu); - hlist_for_each_entry_rcu(n, &head->track_notifier_list, node) + hlist_for_each_entry_rcu(n, &head->track_notifier_list, node, + srcu_read_lock_held(&head->track_srcu)) if (n->track_flush_slot) n->track_flush_slot(kvm, slot, n); srcu_read_unlock(&head->track_srcu, idx); -- 2.17.1