Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030452AbaGDWRU (ORCPT ); Fri, 4 Jul 2014 18:17:20 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57168 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030413AbaGDWRR (ORCPT ); Fri, 4 Jul 2014 18:17:17 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Ellerman , Benjamin Herrenschmidt Subject: [PATCH 3.15 47/66] powerpc/perf: Ensure all EBB register state is cleared on fork() Date: Fri, 4 Jul 2014 15:14:46 -0700 Message-Id: <20140704221424.948136296@linuxfoundation.org> X-Mailer: git-send-email 2.0.1 In-Reply-To: <20140704221422.813435485@linuxfoundation.org> References: <20140704221422.813435485@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Ellerman commit 3df48c981d5a9610e02e9270b1bc4274fb536710 upstream. In commit 330a1eb "Core EBB support for 64-bit book3s" I messed up clear_task_ebb(). It clears some but not all of the task's Event Based Branch (EBB) registers when we duplicate a task struct. That allows a child task to observe the EBBHR & EBBRR of its parent, which it should not be able to do. Fix it by clearing EBBHR & EBBRR. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/include/asm/switch_to.h | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -84,6 +84,8 @@ static inline void clear_task_ebb(struct { #ifdef CONFIG_PPC_BOOK3S_64 /* EBB perf events are not inherited, so clear all EBB state. */ + t->thread.ebbrr = 0; + t->thread.ebbhr = 0; t->thread.bescr = 0; t->thread.mmcr2 = 0; t->thread.mmcr0 = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/