From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932717AbcFBNPu (ORCPT ); Thu, 2 Jun 2016 09:15:50 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:49677 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932123AbcFBNPs (ORCPT ); Thu, 2 Jun 2016 09:15:48 -0400 Date: Thu, 2 Jun 2016 14:15:39 +0100 From: Russell King - ARM Linux To: Simon Marchi Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: Possible race between PTRACE_SETVFPREGS and PTRACE_CONT on ARM? Message-ID: <20160602131539.GA30141@n2100.armlinux.org.uk> References: <574C7CDB.7050103@ericsson.com> <20160530213529.GS19428@n2100.arm.linux.org.uk> <574EDAED.1050902@ericsson.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <574EDAED.1050902@ericsson.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 01, 2016 at 08:54:05AM -0400, Simon Marchi wrote: > On 16-05-30 05:35 PM, Russell King - ARM Linux wrote: > > So, the gdb verisons I have here seem to be particularly poor - but with > > some modifications, I can test out on iMX6 by forcing gdb to do the right > > thing - by inserting a couple of "mov r0, r0" instructions after the > > "break_here" label. > > I see that problem too with older versions, bisecting shows it has been fixed > in commit > > 6e22494e5076 Do not skip prologue for asm (.S) files > > in gdb, which is included in gdb 7.10 and up. > > > With that, on a single CPU, it seems to work correctly every time, but > > if I bring up a secondary CPU I start seeing the same problems you've > > reported - which seems to need the following patch to solve. Please can > > you check whether this resolves your problem? > > Yes that fixes the problem, the test case succeeds every time. I have stared > at those lines in ptrace.c for some time, but couldn't find the problem. Thanks > for looking into it! Hi, can I add a: Tested-by: Simon Marchi tag to the commit please? Many thanks. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.