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 920C8C433ED for ; Mon, 10 May 2021 08:22:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56DE16101B for ; Mon, 10 May 2021 08:22:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230203AbhEJIXP (ORCPT ); Mon, 10 May 2021 04:23:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230118AbhEJIXO (ORCPT ); Mon, 10 May 2021 04:23:14 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A012BC061573; Mon, 10 May 2021 01:22:10 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id t193so216643pgb.4; Mon, 10 May 2021 01:22:10 -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=dhMvoxMJAO0uO8IA2H0TKE6ifTGSTb7TdUN9wUYY1wY=; b=rF+VTgtqNWExfkHPyubomVntp5D64QNIvFRhbWNDq6JUqR6drFXxO2hUq73WoOb4A+ SXOJgOFxNcvt44dK+celf8J3digKOAsuPwycGLvcaaHB/tHudcZcGzYjb+ce+eNCEm5Y w1w7mnQROzs825bb6dI+/Ueisd7QaGmUSyyHHzsOrxhPaFiyt2PlTlOrvpueeDTt24Pz waUwUJhvvCcbpGEmlvPq6YugzUH0ga9pv4L/PLrps/YtrJPioHxChF4RezJHTP89GA54 XVo5oXSsoj8GaAu8br8RIuD/SSQuPkATQhlrx3Ga5B2ACa6PpiZiE5By+lDUoVaUWz1K BkqA== 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=dhMvoxMJAO0uO8IA2H0TKE6ifTGSTb7TdUN9wUYY1wY=; b=jqnXwF3gIcCmTusClvtZ4CmQItUK73p7FS9NTQ9S/tR3WqsJma1s5ZU3I+2sfmH1Rf DiG99sU+YBUuIpRH0CDh5Fe19N8Jf5Unao4v5CeSkG0kkp8p8SQlDhAKhWIsUKLUVBIi 6pXnuOCKp/WZeNhPigiDetAh9giY5yUt8oT7h0fyZGDPBx5McXx9g/NSz66YKhhLhQlQ MGF+kf7q7mYuXJXH75TTghw2tPQSWYPR72lMMqnx+2GgqxyGF75+KW8pyy+exaR8f+RU TNzkT8mTBsDAMzxLuSR/udvKjOvrP6LGh0R/YhOby/nxTfx4ptA7czExYQainqZXl1U/ 2/UQ== X-Gm-Message-State: AOAM532bU/sMZu1SbSgMAEaoHJrNUqaj3/aG+UI1TsKMHryihT+00noM fsEgMcqRTYXHqjU6YIYpzj93fr19DV0= X-Google-Smtp-Source: ABdhPJzIP+6jHymcpdNkCuuBGSX0Azj04jxYye7z94O7cf+ud4WEkbUhx8ymwUTMtSHpOCMpQk7ZVg== X-Received: by 2002:a63:8f17:: with SMTP id n23mr24343609pgd.82.1620634929917; Mon, 10 May 2021 01:22:09 -0700 (PDT) Received: from localhost.localdomain ([103.7.29.6]) by smtp.googlemail.com with ESMTPSA id n8sm10477853pgm.7.2021.05.10.01.22.07 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 May 2021 01:22:09 -0700 (PDT) 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 Subject: [PATCH] KVM: x86: hyper-v: Task srcu lock when accessing kvm_memslots() Date: Mon, 10 May 2021 16:21:59 +0800 Message-Id: <1620634919-4563-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Wanpeng Li WARNING: suspicious RCU usage 5.13.0-rc1 #4 Not tainted ----------------------------- ./include/linux/kvm_host.h:710 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by hyperv_clock/8318: #0: ffffb6b8cb05a7d8 (&hv->hv_lock){+.+.}-{3:3}, at: kvm_hv_invalidate_tsc_page+0x3e/0xa0 [kvm] stack backtrace: CPU: 3 PID: 8318 Comm: hyperv_clock Not tainted 5.13.0-rc1 #4 Call Trace: dump_stack+0x87/0xb7 lockdep_rcu_suspicious+0xce/0xf0 kvm_write_guest_page+0x1c1/0x1d0 [kvm] kvm_write_guest+0x50/0x90 [kvm] kvm_hv_invalidate_tsc_page+0x79/0xa0 [kvm] kvm_gen_update_masterclock+0x1d/0x110 [kvm] kvm_arch_vm_ioctl+0x2a7/0xc50 [kvm] kvm_vm_ioctl+0x123/0x11d0 [kvm] __x64_sys_ioctl+0x3ed/0x9d0 do_syscall_64+0x3d/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae kvm_memslots() will be called by kvm_write_guest(), so we should take the srcu lock. Fixes: e880c6ea5 (KVM: x86: hyper-v: Prevent using not-yet-updated TSC page by secondary CPUs) Signed-off-by: Wanpeng Li --- arch/x86/kvm/hyperv.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index f98370a3..f00830e 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1172,6 +1172,7 @@ void kvm_hv_invalidate_tsc_page(struct kvm *kvm) { struct kvm_hv *hv = to_kvm_hv(kvm); u64 gfn; + int idx; if (hv->hv_tsc_page_status == HV_TSC_PAGE_BROKEN || hv->hv_tsc_page_status == HV_TSC_PAGE_UNSET || @@ -1190,9 +1191,16 @@ void kvm_hv_invalidate_tsc_page(struct kvm *kvm) gfn = hv->hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT; hv->tsc_ref.tsc_sequence = 0; + + /* + * Take the srcu lock as memslots will be accessed to check the gfn + * cache generation against the memslots generation. + */ + idx = srcu_read_lock(&kvm->srcu); if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence))) hv->hv_tsc_page_status = HV_TSC_PAGE_BROKEN; + srcu_read_unlock(&kvm->srcu, idx); out_unlock: mutex_unlock(&hv->hv_lock); -- 2.7.4