From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8589EC49ED7 for ; Thu, 19 Sep 2019 10:25:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 65D212196E for ; Thu, 19 Sep 2019 10:25:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389323AbfISKZ6 (ORCPT ); Thu, 19 Sep 2019 06:25:58 -0400 Received: from ozlabs.org ([203.11.71.1]:47641 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389206AbfISKZ5 (ORCPT ); Thu, 19 Sep 2019 06:25:57 -0400 Received: by ozlabs.org (Postfix, from userid 1034) id 46YtKb2HHTz9sPM; Thu, 19 Sep 2019 20:25:55 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: bc01bdf6c5df5023272a7399962cf64f8fedc93e In-Reply-To: <20190910131513.30499-1-ravi.bangoria@linux.ibm.com> To: Ravi Bangoria , mikey@neuling.org From: Michael Ellerman Cc: Ravi Bangoria , linux-kernel@vger.kernel.org, paulus@samba.org, "Naveen N . Rao" , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v2] powerpc/watchpoint: Disable watchpoint hit by larx/stcx instructions Message-Id: <46YtKb2HHTz9sPM@ozlabs.org> Date: Thu, 19 Sep 2019 20:25:55 +1000 (AEST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2019-09-10 at 13:15:13 UTC, Ravi Bangoria wrote: > If watchpoint exception is generated by larx/stcx instructions, the > reservation created by larx gets lost while handling exception, and > thus stcx instruction always fails. Generally these instructions are > used in a while(1) loop, for example spinlocks. And because stcx > never succeeds, it loops forever and ultimately hangs the system. > > Note that ptrace anyway works in one-shot mode and thus for ptrace > we don't change the behaviour. It's up to ptrace user to take care > of this. > > Signed-off-by: Ravi Bangoria > Acked-by: Naveen N. Rao Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/bc01bdf6c5df5023272a7399962cf64f8fedc93e cheers