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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 C22E3C433E0 for ; Sat, 13 Mar 2021 00:52:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CD9564F8E for ; Sat, 13 Mar 2021 00:52:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232731AbhCMAwD (ORCPT ); Fri, 12 Mar 2021 19:52:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229523AbhCMAvh (ORCPT ); Fri, 12 Mar 2021 19:51:37 -0500 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5BA9C061574; Fri, 12 Mar 2021 16:51:36 -0800 (PST) Received: by mail-pj1-x102a.google.com with SMTP id q6-20020a17090a4306b02900c42a012202so11865649pjg.5; Fri, 12 Mar 2021 16:51:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=dRSHTuJXO3IQ/87o0yBBwkk9pun6bTQgoCwjJVxdHws=; b=qtiWt0VH65vYAQRqSWgkuE/sWwW3Ol15GPaIvTnOeXCaK2iMNYEvDf1RqkLjyOlDrr vk1YcWKcaDEg/422Y46tItRwFlerZY/G/uKQDigI7/NLg2GDacaBQcXEjAQVaVtnFRxU NexbK/b1wqT8fZWym+XTubm5aZqyu9lnQJXwg41rIhQ/ENgCFMIdynjt8fg+nSoRhD1Q tAmzOhgH8r2Ut7Jlbv0hXXhFAVnn982EnI4FgWeXZYQCJEE7XQGQItyQOQxOzA3hljTf usvhgpc/6ZTT1jb2jb7oRCh9O3BTGq/CavBULL+sBqXtVN8QEYGzuI/IeUd1nSzep8Vo vwGg== 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=dRSHTuJXO3IQ/87o0yBBwkk9pun6bTQgoCwjJVxdHws=; b=iL64SGp/uE2C+Gyhzy8UxRT7/VPpxLJRtca6coc4OXKuw4Nf++QsROClEHUidMS5Ra GfSETEsfqiglS5SI0yyttQRWBTTrjMzizNIwRPD+qUCNAmiDD0okmetkJGaH7qsLjTiY tNyEReOGwnzrPuf1s7u95obhSHJn6jXJngZ/UVFe1QMyasGXOeq+90ZOPjaN0uXZ2Wt0 8uT0B8o00r4ldWnE4bO3Zt1pgxvnoJsnJYKyOF3fnjkBXI/1ncUlmWYY/mnxen9fLSn7 YD2lbL+sz0tIKn/qlJL6QtVvq/rE+uWwgAoam/MJygAWHXWlW2T5YyRrEPnfuI5lU26t +Ulg== X-Gm-Message-State: AOAM533EaxR59QFsPfm3HePXaKMZeH0ZG4B/nHrpmSGcbjwkdTwl/gWl dl7CueLpyysRa2QJU0HugS+KPbbDAf8= X-Google-Smtp-Source: ABdhPJx7CPOsQEzdnXkvuUX6xzBs+2dK2AAtC1rOSPg65XZ2aZYOJHwYyTFLUXpXCo6d4pEFVIc9yQ== X-Received: by 2002:a17:902:eb11:b029:e4:a5c3:4328 with SMTP id l17-20020a170902eb11b02900e4a5c34328mr1084621plb.7.1615596696086; Fri, 12 Mar 2021 16:51:36 -0800 (PST) Received: from localhost.localdomain ([103.7.29.6]) by smtp.googlemail.com with ESMTPSA id i10sm14380849pjm.1.2021.03.12.16.51.33 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 12 Mar 2021 16:51:35 -0800 (PST) From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Mark Rutland , Thomas Gleixner Subject: [PATCH v2] x86/kvm: Fix broken irq restoration in kvm_wait Date: Sat, 13 Mar 2021 08:51:25 +0800 Message-Id: <1615596685-22269-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li After commit 997acaf6b4b59c (lockdep: report broken irq restoration), the guest splatting below during boot: raw_local_irq_restore() called with IRQs enabled WARNING: CPU: 1 PID: 169 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x26/0x30 Modules linked in: hid_generic usbhid hid CPU: 1 PID: 169 Comm: systemd-udevd Not tainted 5.11.0+ #25 RIP: 0010:warn_bogus_irq_restore+0x26/0x30 Call Trace: kvm_wait+0x76/0x90 __pv_queued_spin_lock_slowpath+0x285/0x2e0 do_raw_spin_lock+0xc9/0xd0 _raw_spin_lock+0x59/0x70 lockref_get_not_dead+0xf/0x50 __legitimize_path+0x31/0x60 legitimize_root+0x37/0x50 try_to_unlazy_next+0x7f/0x1d0 lookup_fast+0xb0/0x170 path_openat+0x165/0x9b0 do_filp_open+0x99/0x110 do_sys_openat2+0x1f1/0x2e0 do_sys_open+0x5c/0x80 __x64_sys_open+0x21/0x30 do_syscall_64+0x32/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xae The irqflags handling in kvm_wait() which ends up doing: local_irq_save(flags); safe_halt(); local_irq_restore(flags); which triggered a new consistency checking, we generally expect local_irq_save() and local_irq_restore() to be pared and sanely nested, and so local_irq_restore() expects to be called with irqs disabled. This patch fixes it by playing local_irq_disable()/enable() directly. Cc: Mark Rutland Cc: Thomas Gleixner Signed-off-by: Wanpeng Li --- v1 -> v2: * select the alternative fix arch/x86/kernel/kvm.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 5e78e01..7127aef 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -836,12 +836,13 @@ static void kvm_kick_cpu(int cpu) static void kvm_wait(u8 *ptr, u8 val) { - unsigned long flags; + bool disabled = irqs_disabled(); if (in_nmi()) return; - local_irq_save(flags); + if (!disabled) + local_irq_disable(); if (READ_ONCE(*ptr) != val) goto out; @@ -851,13 +852,14 @@ static void kvm_wait(u8 *ptr, u8 val) * for irq enabled case to avoid hang when lock info is overwritten * in irq spinlock slowpath and no spurious interrupt occur to save us. */ - if (arch_irqs_disabled_flags(flags)) + if (disabled) halt(); else safe_halt(); out: - local_irq_restore(flags); + if (!disabled) + local_irq_enable(); } #ifdef CONFIG_X86_32 -- 2.7.4