From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753326AbaIALsG (ORCPT ); Mon, 1 Sep 2014 07:48:06 -0400 Received: from gw-1.arm.linux.org.uk ([78.32.30.217]:38667 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751500AbaIALsE (ORCPT ); Mon, 1 Sep 2014 07:48:04 -0400 Date: Mon, 1 Sep 2014 12:47:51 +0100 From: Russell King - ARM Linux To: AKASHI Takahiro Cc: Will Deacon , "linaro-kernel@lists.linaro.org" , Kees Cook , Catalin Marinas , "arndb@arndb.de" , LKML , Deepak Saxena , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v6 2/6] arm64: ptrace: allow tracer to skip a system call Message-ID: <20140901114751.GG30401@n2100.arm.linux.org.uk> References: <1408611405-8943-1-git-send-email-takahiro.akashi@linaro.org> <1408611405-8943-3-git-send-email-takahiro.akashi@linaro.org> <53F69045.7010301@linaro.org> <20140826175128.GD23445@arm.com> <53FD72E2.4020103@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53FD72E2.4020103@linaro.org> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 27, 2014 at 02:55:46PM +0900, AKASHI Takahiro wrote: > 1) > setting x0 to -ENOSYS is necessary because, otherwise, user-issued syscall(-1) will > return a bogus value when audit tracing is on. > > Please note that, on arm, > not traced traced > ------ ------ > syscall(-1) aborted OOPs(BUG_ON) > syscall(-3000) aborted aborted > syscall(1000) ENOSYS ENOSYS Two points here: 1. You've found a case which causes a BUG_ON(). Where is the bug report for this, so the problem can be investigated and resolved? 2. What do you mean by "aborted" ? Please, if you find a problem with 32-bit ARM, report it. Don't hide it, because hiding it can be a security issue or in the case of BUG_ON(), it could be a denial of service issue. As you're part of Linaro, I would have thought you'd be more responsible in this regard - after all, Linaro is supposed to be about improving the ARM kernel... Maybe I got that wrong, and Linaro is actually about ensuring that the ARM kernel is stuffed full of broken features? -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net. From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Mon, 1 Sep 2014 12:47:51 +0100 Subject: [PATCH v6 2/6] arm64: ptrace: allow tracer to skip a system call In-Reply-To: <53FD72E2.4020103@linaro.org> References: <1408611405-8943-1-git-send-email-takahiro.akashi@linaro.org> <1408611405-8943-3-git-send-email-takahiro.akashi@linaro.org> <53F69045.7010301@linaro.org> <20140826175128.GD23445@arm.com> <53FD72E2.4020103@linaro.org> Message-ID: <20140901114751.GG30401@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Aug 27, 2014 at 02:55:46PM +0900, AKASHI Takahiro wrote: > 1) > setting x0 to -ENOSYS is necessary because, otherwise, user-issued syscall(-1) will > return a bogus value when audit tracing is on. > > Please note that, on arm, > not traced traced > ------ ------ > syscall(-1) aborted OOPs(BUG_ON) > syscall(-3000) aborted aborted > syscall(1000) ENOSYS ENOSYS Two points here: 1. You've found a case which causes a BUG_ON(). Where is the bug report for this, so the problem can be investigated and resolved? 2. What do you mean by "aborted" ? Please, if you find a problem with 32-bit ARM, report it. Don't hide it, because hiding it can be a security issue or in the case of BUG_ON(), it could be a denial of service issue. As you're part of Linaro, I would have thought you'd be more responsible in this regard - after all, Linaro is supposed to be about improving the ARM kernel... Maybe I got that wrong, and Linaro is actually about ensuring that the ARM kernel is stuffed full of broken features? -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net.