Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161140AbWBQBGm (ORCPT ); Thu, 16 Feb 2006 20:06:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161142AbWBQBGm (ORCPT ); Thu, 16 Feb 2006 20:06:42 -0500 Received: from smtp.osdl.org ([65.172.181.4]:29330 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1161140AbWBQBGl (ORCPT ); Thu, 16 Feb 2006 20:06:41 -0500 Date: Thu, 16 Feb 2006 17:06:22 -0800 (PST) From: Linus Torvalds To: Chuck Ebbert <76306.1226@compuserve.com> cc: Andrew Morton , linux-kernel Subject: Re: [patch] i386: fix singlestepping though a syscall In-Reply-To: <200602161914_MC3-1-B89C-55BE@compuserve.com> Message-ID: References: <200602161914_MC3-1-B89C-55BE@compuserve.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 975 Lines: 30 On Thu, 16 Feb 2006, Chuck Ebbert wrote: > > Singlestep through a syscall using vsyscall-sysenter had two bugs: > > 1. Setting TIF_SINGLESTEP is not enough to force > do_notify_resume() to be run on return to user; > TIF_IRET must also be set. Interesting, but I think you pinpointed the _real_ bug. TIF_SINGLESTEP very much should be enough to force do_notify_resume() to be run on return to user space. Sounds like somebody is testing _TIF_WORK_MASK rather than _TIF_ALLWORK_MASK. I'd suspect the "work_pending" case. Looks like we miss testing the TIF flags there. Oh, actually, I think you should just remove the clearing of _TIF_SINGLESTEP from _TIF_WORK_MASK. Does that fix the bug. Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/