Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752053AbZLRBCw (ORCPT ); Thu, 17 Dec 2009 20:02:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751309AbZLRBCu (ORCPT ); Thu, 17 Dec 2009 20:02:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35064 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750788AbZLRBCu (ORCPT ); Thu, 17 Dec 2009 20:02:50 -0500 Date: Fri, 18 Dec 2009 01:56:50 +0100 From: Oleg Nesterov To: "K.Prasad" , Alan Stern , Frederic Weisbecker , Ingo Molnar , Roland McGrath Cc: linux-kernel@vger.kernel.org, utrace-devel@redhat.com Subject: x86: do_debug && PTRACE_SINGLESTEP broken by 08d68323d1f0c34452e614263b212ca556dae47f Message-ID: <20091218005650.GA20667@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1064 Lines: 31 Hi. do_debug() is obviously wrong wrt PTRACE_SINGLESTEP/TIF_SINGLESTEP, no? Afaics this was broken by hw-breakpoints: modifying generic debug exception to use thread-specific debug registers commit 08d68323d1f0c34452e614263b212ca556dae47f To verify, the "patch" below fixes the stepping for me, not sure what is the proper fix... Oleg. --- arch/x86/kernel/traps.c~ 2009-12-18 00:20:49.000000000 +0100 +++ arch/x86/kernel/traps.c 2009-12-18 01:44:05.000000000 +0100 @@ -575,7 +575,7 @@ dotraplinkage void __kprobes do_debug(st regs->flags &= ~X86_EFLAGS_TF; } si_code = get_si_code(tsk->thread.debugreg6); - if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS)) +// if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS)) send_sigtrap(tsk, regs, error_code, si_code); preempt_conditional_cli(regs); -- 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/