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=unavailable 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 30235C3A5A6 for ; Thu, 19 Sep 2019 10:57:38 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DD102217D6 for ; Thu, 19 Sep 2019 10:57:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD102217D6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46Yv273pNwzF4xr for ; Thu, 19 Sep 2019 20:57:35 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46YtKh0T2bzF4Xs for ; Thu, 19 Sep 2019 20:26:00 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au 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 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) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ravi Bangoria , "Naveen N . Rao" , linuxppc-dev@lists.ozlabs.org, paulus@samba.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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