From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759965AbcLAPeF (ORCPT ); Thu, 1 Dec 2016 10:34:05 -0500 Received: from p3plsmtps2ded03.prod.phx3.secureserver.net ([208.109.80.60]:37834 "EHLO p3plsmtps2ded03.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755340AbcLAPeD (ORCPT ); Thu, 1 Dec 2016 10:34:03 -0500 x-originating-ip: 72.167.245.219 From: kys@exchange.microsoft.com To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com, leann.ogasawara@canonical.com Cc: "K. Y. Srinivasan" Subject: [PATCH 12/15] hv: don't reset hv_context.tsc_page on crash Date: Thu, 1 Dec 2016 09:28:49 -0800 Message-Id: <1480613332-7788-12-git-send-email-kys@exchange.microsoft.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1480613332-7788-1-git-send-email-kys@exchange.microsoft.com> References: <1480613287-7748-1-git-send-email-kys@exchange.microsoft.com> <1480613332-7788-1-git-send-email-kys@exchange.microsoft.com> Reply-To: kys@microsoft.com X-CMAE-Envelope: MS4wfM9xhNmSGO8n4Xy2mN1ehI3gkb+CxtN5nPQTs4R6TazFAdtQ0ZY0GYNgyhiDoQq9c0GlUhcaTrrJxxl55G6Hsd9sZ+Zs7CaF+DmpMcM7oOmjWl8eTioN I5J4nE6XyHYkuulrWzUWGPH0RdbcYtZkJnoHvt+ZCofHNkuOO6lUXlILDzmK9YLdHN9wdftZ51zK54mpE58Sjgl1z8b+TznSTDUpREhzv54IJtTGuubLfToC Bj17Q/9NqfLQCgZCrHR7KP+MLH20Hlrj9LrBdmcLwGDRc6bBZZ83EKp4OYv+14OzlbdjoCGz37Am8aoxiiN2Ibci8LcMxRWSrAcNKGV0gjwRZI/ycK/dDZKX 8C/sfffLCZsHO0EupRFFAIAgbPLChJEApao18sRTc7qRGO2bbHPz/dKHWGlOj9YZT9n2DymtCh8ODsKItypumhVUuUhKHF2eyzE2fF/u8VzVzyPscD8= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vitaly Kuznetsov It may happen that secondary CPUs are still alive and resetting hv_context.tsc_page will cause a consequent crash in read_hv_clock_tsc() as we don't check for it being not NULL there. It is safe as we're not freeing this page anyways. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan --- drivers/hv/hv.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 4ece040..04a0fd8 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -309,9 +309,10 @@ void hv_cleanup(bool crash) hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); - if (!crash) + if (!crash) { vfree(hv_context.tsc_page); - hv_context.tsc_page = NULL; + hv_context.tsc_page = NULL; + } } #endif } -- 1.7.4.1