From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933230AbZKXUMQ (ORCPT ); Tue, 24 Nov 2009 15:12:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932915AbZKXUMP (ORCPT ); Tue, 24 Nov 2009 15:12:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:11205 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932909AbZKXUMO (ORCPT ); Tue, 24 Nov 2009 15:12:14 -0500 Date: Tue, 24 Nov 2009 21:01:52 +0100 From: Oleg Nesterov To: Alexey Dobriyan , Ananth Mavinakayanahalli , Christoph Hellwig , "Frank Ch. Eigler" , Ingo Molnar , Peter Zijlstra , Roland McGrath Cc: linux-kernel@vger.kernel.org, utrace-devel@redhat.com Subject: [RFC,PATCH 07/14] ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping Message-ID: <20091124200152.GA5789@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 (already in mm: ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping.patch) Suggested by Roland. Unlike powepc, x86 always calls tracehook_report_syscall_exit(step) with step = 0, and sends the trap by hand. This results in unnecessary SIGTRAP when PTRACE_SINGLESTEP follows the syscall-exit stop. Change syscall_trace_leave() to pass the correct "step" argument to tracehook and remove the send_sigtrap() logic. Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath --- arch/x86/kernel/ptrace.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) --- V1/arch/x86/kernel/ptrace.c~7_X86_CONVERT_SYSCALL_LEAVE 2009-11-24 19:52:11.000000000 +0100 +++ V1/arch/x86/kernel/ptrace.c 2009-11-24 19:52:12.000000000 +0100 @@ -1528,29 +1528,22 @@ asmregparm long syscall_trace_enter(stru asmregparm void syscall_trace_leave(struct pt_regs *regs) { + bool step; + if (unlikely(current->audit_context)) audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax); if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) trace_sys_exit(regs, regs->ax); - if (test_thread_flag(TIF_SYSCALL_TRACE)) - tracehook_report_syscall_exit(regs, 0); - /* * If TIF_SYSCALL_EMU is set, we only get here because of * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP). * We already reported this syscall instruction in - * syscall_trace_enter(), so don't do any more now. - */ - if (unlikely(test_thread_flag(TIF_SYSCALL_EMU))) - return; - - /* - * If we are single-stepping, synthesize a trap to follow the - * system call instruction. + * syscall_trace_enter(). */ - if (test_thread_flag(TIF_SINGLESTEP) && - tracehook_consider_fatal_signal(current, SIGTRAP)) - send_sigtrap(current, regs, 0, TRAP_BRKPT); + step = unlikely(test_thread_flag(TIF_SINGLESTEP)) && + !test_thread_flag(TIF_SYSCALL_EMU); + if (step || test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, step); }