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[23.128.96.18]) by mx.google.com with ESMTP id g27si1585157ejb.616.2021.05.12.19.02.46; Wed, 12 May 2021 19:03:10 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b="H0Vf/Pzv"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230184AbhEMCBU (ORCPT + 99 others); Wed, 12 May 2021 22:01:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230048AbhEMCBM (ORCPT ); Wed, 12 May 2021 22:01:12 -0400 Received: from mail-pg1-x529.google.com (mail-pg1-x529.google.com [IPv6:2607:f8b0:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3FD7C061574; Wed, 12 May 2021 19:00:02 -0700 (PDT) Received: by mail-pg1-x529.google.com with SMTP id l70so5146412pga.1; Wed, 12 May 2021 19:00:02 -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:in-reply-to:references; bh=v/Eg2aLgMEl3C9DBh5TiPixhOAqZrBo8ju/YFJi/mRs=; b=H0Vf/PzvX1Az7P3qelVGuIU3tInxn8PVF40BcYsq29zt+CjKyrEcg8OJGUm7V7Vw6z 8xLwCXBwBcfozuhpSdADU4XabIQxvQ0WL5ULDTgQrtmv24EfQk8CIFRyMQ8XFrec++ng NU1EefB1Vg3LaDJ6AMhhqaYSWYB+ujA+1KiDdFgZWvD9FQirxc5J3cScWqA9eJDr6cfY tKPuxK0fgiQzze8lQRkj01lDBuv1Fd/lmfJiLwLTX3CHqphuhql0kR4mB/wH4CJJ8dDG bnuUjk40oFgvnzqtUYlTwdvEnks0ZWKMn2knaehUGKeXzeJ1pJBzkmxy8ol8js6uRwW2 v3Hg== 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:in-reply-to :references; bh=v/Eg2aLgMEl3C9DBh5TiPixhOAqZrBo8ju/YFJi/mRs=; b=AeC3/M+HSJda7iksqqEOyndFTTlxNmGF3vv3fjy+AFyoCcMXTbOpV5lju3Eb/0HcI6 Bk1yinnss1AzA0Z7d6bIb3zOX5yuv1pAGCkiP7kupp/KyZ7b9qDbPqdt58CmN97JMyUI hycKyFfc+8pOFkt1a+uaLpUQm8ItHQqIbSTLDWEeaaT/r+aecsNOzFLS8PDxcl3q2SLP IHFbUgxG/FtqiQ28P8BIStRWUuJ+F19FfI6heFpdd/zbh9WzvSNMLFjRYIPELbXfPSzS UFdrqYrTtjWdc5oSdy8aoHPQSiHR0zWrlYMdu1gEAhb6W3vApt+Ge/Ic7oP19Ql6o0Jb 7Q4w== X-Gm-Message-State: AOAM530m1W8HfTMmPqrEJPCLRfpzp1plagUwOkYa54ZnKx2hn1IPIWsW EtPQNm5rgdd4QSBwQXuMYSdn/jdsULA= X-Received: by 2002:a17:90a:510d:: with SMTP id t13mr1782767pjh.1.1620871202379; Wed, 12 May 2021 19:00:02 -0700 (PDT) Received: from localhost.localdomain ([103.7.29.6]) by smtp.googlemail.com with ESMTPSA id w123sm812742pfw.151.2021.05.12.19.00.00 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 May 2021 19:00:02 -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 v2 4/4] KVM: x86: hyper-v: Task srcu lock when accessing kvm_memslots() Date: Thu, 13 May 2021 09:59:49 +0800 Message-Id: <1620871189-4763-3-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1620871189-4763-1-git-send-email-wanpengli@tencent.com> References: <1620871189-4763-1-git-send-email-wanpengli@tencent.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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) Reviewed-by: Vitaly Kuznetsov 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