Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754147Ab3DRSrG (ORCPT ); Thu, 18 Apr 2013 14:47:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50741 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753776Ab3DRSrE (ORCPT ); Thu, 18 Apr 2013 14:47:04 -0400 Date: Thu, 18 Apr 2013 20:44:10 +0200 From: Oleg Nesterov To: Andrew Morton Cc: Alan Stern , Frederic Weisbecker , Ingo Molnar , Jan Kratochvil , Prasad , linux-kernel@vger.kernel.org Subject: [PATCH 1/6] ptrace/x86: simplify the "disable" logic in ptrace_write_dr7() Message-ID: <20130418184410.GA4425@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130418184350.GA4407@redhat.com> 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: 2457 Lines: 79 ptrace_write_dr7() looks unnecessarily overcomplicated. We can factor out ptrace_modify_breakpoint() and do not do "continue" twice, just we need to pass the proper "disabled" argument to ptrace_modify_breakpoint(). Signed-off-by: Oleg Nesterov Acked-by: Frederic Weisbecker --- arch/x86/kernel/ptrace.c | 40 +++++++++++++++------------------------- 1 files changed, 15 insertions(+), 25 deletions(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 7a98b21..0649f16 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -637,9 +637,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data) struct thread_struct *thread = &(tsk->thread); unsigned long old_dr7; int i, orig_ret = 0, rc = 0; - int enabled, second_pass = 0; - unsigned len, type; - struct perf_event *bp; + int second_pass = 0; data &= ~DR_CONTROL_RESERVED; old_dr7 = ptrace_get_dr7(thread->ptrace_bps); @@ -649,30 +647,22 @@ restore: * appropriate changes to each. */ for (i = 0; i < HBP_NUM; i++) { - enabled = decode_dr7(data, i, &len, &type); - bp = thread->ptrace_bps[i]; - - if (!enabled) { - if (bp) { - /* - * Don't unregister the breakpoints right-away, - * unless all register_user_hw_breakpoint() - * requests have succeeded. This prevents - * any window of opportunity for debug - * register grabbing by other users. - */ - if (!second_pass) - continue; - - rc = ptrace_modify_breakpoint(bp, len, type, - tsk, 1); - if (rc) - break; - } - continue; + unsigned len, type; + bool disabled = !decode_dr7(data, i, &len, &type); + struct perf_event *bp = thread->ptrace_bps[i]; + + if (disabled) { + /* + * Don't unregister the breakpoints right-away, unless + * all register_user_hw_breakpoint() requests have + * succeeded. This prevents any window of opportunity + * for debug register grabbing by other users. + */ + if (!bp || !second_pass) + continue; } - rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0); + rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled); if (rc) break; } -- 1.5.5.1 -- 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/