Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B6966C433EF for ; Wed, 24 Nov 2021 13:39:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344543AbhKXNmK (ORCPT ); Wed, 24 Nov 2021 08:42:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:55788 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350394AbhKXNji (ORCPT ); Wed, 24 Nov 2021 08:39:38 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1FBCF63231; Wed, 24 Nov 2021 12:56:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637758611; bh=QNmNlGbItnQwTF/I01u34QXi8OEmR0WdhO+uw//JHJg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YMbKgWrKQqedlXDR4+JqEilOe75g7D4MALj63xS14jqKqzyUbUw0TC4zF7S9m4Dao D/zW5zkQO5st9NVKcTagxJbAJSPTKU9ykxSmsv2mkO0X1fbvCSOPw/mr75LEbXGVi5 BD5B/lvJZtUmAHXnYQrppjp6dcJO3z3jVm3g0UcY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vitaly Kuznetsov , Sean Christopherson , Wei Liu Subject: [PATCH 5.10 126/154] x86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails Date: Wed, 24 Nov 2021 12:58:42 +0100 Message-Id: <20211124115706.372150617@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115702.361983534@linuxfoundation.org> References: <20211124115702.361983534@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson commit daf972118c517b91f74ff1731417feb4270625a4 upstream. Check for a valid hv_vp_index array prior to derefencing hv_vp_index when setting Hyper-V's TSC change callback. If Hyper-V setup failed in hyperv_init(), the kernel will still report that it's running under Hyper-V, but will have silently disabled nearly all functionality. BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc2+ #75 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:set_hv_tscchange_cb+0x15/0xa0 Code: <8b> 04 82 8b 15 12 17 85 01 48 c1 e0 20 48 0d ee 00 01 00 f6 c6 08 ... Call Trace: kvm_arch_init+0x17c/0x280 kvm_init+0x31/0x330 vmx_init+0xba/0x13a do_one_initcall+0x41/0x1c0 kernel_init_freeable+0x1f2/0x23b kernel_init+0x16/0x120 ret_from_fork+0x22/0x30 Fixes: 93286261de1b ("x86/hyperv: Reenlightenment notifications support") Cc: stable@vger.kernel.org Cc: Vitaly Kuznetsov Signed-off-by: Sean Christopherson Reviewed-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20211104182239.1302956-2-seanjc@google.com Signed-off-by: Wei Liu Signed-off-by: Greg Kroah-Hartman --- arch/x86/hyperv/hv_init.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -176,6 +176,9 @@ void set_hv_tscchange_cb(void (*cb)(void return; } + if (!hv_vp_index) + return; + hv_reenlightenment_cb = cb; /* Make sure callback is registered before we write to MSRs */