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[23.128.96.18]) by mx.google.com with ESMTP id g5si8404058jan.100.2021.05.19.11.03.35; Wed, 19 May 2021 11:03:54 -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=tqDT9Kxa; 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 S1349056AbhERMD1 (ORCPT + 99 others); Tue, 18 May 2021 08:03:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348967AbhERMC7 (ORCPT ); Tue, 18 May 2021 08:02:59 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6831C061573; Tue, 18 May 2021 05:01:41 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id pi6-20020a17090b1e46b029015cec51d7cdso1409791pjb.5; Tue, 18 May 2021 05:01:41 -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=p6jAyFEHVFCxlZGpGxYbrWuXzrXvA1+9+mG4jRlrIQk=; b=tqDT9KxazuovNRmwbS4IDOkVHtDo6mjoMa1uRcY3W2LdtNltNuSGmnD9tTl3RSQRPV aQ40q/O/ydu3Y+oKrfdL8Grga0tnbpgOaQ/H7F+2BDsN/WI0LNNlNaQ7OSpCDa76b6Zt zNIPVabi3l57HxgDO1vD/JsZWAZ47QxOOfEm9NrNrxsXoLQbYTm8pX1ag0ODn9yviFCx iLXc4NAHQqB/9TpyZ12s/FfjZLVLOia3t/kfxgqSrdOMzLmJLR2DThE3+NMd54ITF8us 0zuq6SW+9Hf0wB9ZaKI4HMvSFxK8Q08syOS6UtQcM7P3MJmdfqM4e/6rkIDWPMNCE13E t8Hw== 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=p6jAyFEHVFCxlZGpGxYbrWuXzrXvA1+9+mG4jRlrIQk=; b=RCdIfmXn7beW5k4nJPNKJGKCK0+Dxoga/D/EF60MDE5TTn843KzJtV0X/2yoHMnHPx cEGhghxDJziwVAPEjUz8JPQwHOYTK7bKO9wos3sP1pJT9XlAhhayhgykxpgTsdpn5IwT bLK+3fQVjNQEQbB5pooswYYPLhhxY6wHygR9RPJ17OqOA8zgWtUikQ+MPQG0I3pNkVZ9 mTe/WVDpurGZ5UVE6/pzUlvAYadZZntaNrmxPvrXral5/Fo5rD2IBTRU7ZeL+luUTjL6 hEXgHsvPFSu/ub+szPZtjb4lyuw+Y4ogAzmICl/5emSsS033UqRw+2C6C41gQkZ3WZw5 b3Lg== X-Gm-Message-State: AOAM530DLRnn56OvMbSfwsNtPKYPXd3pzsBs0nAd5iXV0ncmzgk69LzD fh4MJa7DppRU1XUFoAxGq/7teA1O/sk= X-Received: by 2002:a17:90b:ed5:: with SMTP id gz21mr5200301pjb.102.1621339301043; Tue, 18 May 2021 05:01:41 -0700 (PDT) Received: from localhost.localdomain ([203.205.141.53]) by smtp.googlemail.com with ESMTPSA id l20sm12757394pjq.38.2021.05.18.05.01.38 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 May 2021 05:01:40 -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 v4 4/5] KVM: X86: hyper-v: Task srcu lock when accessing kvm_memslots() Date: Tue, 18 May 2021 05:00:34 -0700 Message-Id: <1621339235-11131-4-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1621339235-11131-1-git-send-email-wanpengli@tencent.com> References: <1621339235-11131-1-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 f98370a39936..f00830e5202f 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); -- 2.25.1