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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 8F5E9C433DF for ; Wed, 27 May 2020 09:55:37 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 59C20212CC for ; Wed, 27 May 2020 09:55:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="jfRUGvem"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="B/rHUZhH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59C20212CC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zhCZ6gz+LGXuN3qqzUPoPIXxgCAPp9vdaOX20qdUIyo=; b=jfRUGvemtw9l/7 irEqIMla13qChHYW7XlveBT3N/cn9MSqhHqWpxDdl1GEa+jLjLICyNGnDgNfc+1RBE8agHMqX9KlC tGeL7jKwiddZO/wBGpoiKWXC8CT+NxIY4kvb9R7UFpxtAEsWcSmrfnfOvck63hmeDKM9gn5oQrcNM J93OkfsUQAmV11Zb/k8jY4EmfACiIjk5lSqFklwRGGWyLyHfNCNjYp/VoImyI7H42O5O08c3HWfrA P9wN/F1lttPE2oIqxF32MMyzrDoH745juYKlDgd+eo0WCAblwfyhk8hmwqG/gosbxgkL2WoBAwYiE 2I8bb1RSMsRNIybtBtJw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdsme-0001ze-W8; Wed, 27 May 2020 09:55:36 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdsmb-0001xm-PX for linux-arm-kernel@lists.infradead.org; Wed, 27 May 2020 09:55:35 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5DD8F2088E; Wed, 27 May 2020 09:55:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590573333; bh=0vEyKxh0OHGJ9gF0R7NIKNktw24Wv6pQ4lvQk1y2efc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=B/rHUZhHlceJDTiD9oSe5JYsGHNHGVPib/TpRBweLOk3z0/bdBhib+7ZFEf32KPP3 67oygptKA6VxdYQ64m5478zeA/FZbiMO8MJbtxCp4YIJQpx+N65PYL/IqAu4jzzltl LKaCXNTiKOv8JDw0w780+yxXVfFg7OsjwlyRyaEw= Date: Wed, 27 May 2020 10:55:29 +0100 From: Will Deacon To: Keno Fischer Subject: Re: arm64: Register modification during syscall entry/exit stop Message-ID: <20200527095528.GC11111@willie-the-truck> References: <20200519081551.GA9980@willie-the-truck> <20200520174149.GB27629@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200527_025533_857063_2820CDC6 X-CRM114-Status: GOOD ( 13.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , Kyle Huey , Oleg Nesterov , linux-arm-kernel@lists.infradead.org, Linux Kernel Mailing List Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun, May 24, 2020 at 02:56:35AM -0400, Keno Fischer wrote: > Just ran into this issue again, with what I think may be most compelling > example yet why this is problematic: > > The tracee incurred a signal, we PTRACE_SYSEMU'd to the rt_sigreturn, > which the tracer tried to emulate by applying the state from the signal frame. > However, the PTRACE_SYSEMU stop is a syscall-stop, so the tracer's write > to x7 was ignored and x7 retained the value it had in the signal handler, > which broke the tracee. Yeah, that sounds like a good justification to add a way to stop this. Could you send a patch, please? Interestingly, I *thought* the current behaviour was needed by strace, but I can't find anything there that seems to require it. Oh well, we're stuck with it anyway. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel