From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: m68k, signals and single-stepping Date: Thu, 30 Sep 2010 13:05:04 +0100 Message-ID: <20100930120504.GM19804@ZenIV.linux.org.uk> References: <20100930055823.GK19804@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:40949 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755309Ab0I3MFF (ORCPT ); Thu, 30 Sep 2010 08:05:05 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Andreas Schwab Cc: Geert Uytterhoeven , Linux/m68k On Thu, Sep 30, 2010 at 10:21:47AM +0200, Andreas Schwab wrote: > Geert Uytterhoeven writes: > > >> So what's that SIGTRAP on exit from syscall in single-stepping mode for? > > The trace exception is low priority exception that is executed after all > other exceptions are processed. So if the cpu single steps over a trap > insns, the trace exception processing is started when the trap exception > processing is complete, which is just before the cpu starts executing > the trap exception handler in the kernel. You want the SIGTRAP to be > sent to the user process, so you have to delay sending it until the > kernel returns to user space. Um... What's wrong with doing that from trap_c()?