From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932068AbZKKVhI (ORCPT ); Wed, 11 Nov 2009 16:37:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759334AbZKKVhF (ORCPT ); Wed, 11 Nov 2009 16:37:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:6457 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759324AbZKKVg6 (ORCPT ); Wed, 11 Nov 2009 16:36:58 -0500 Date: Wed, 11 Nov 2009 22:32:01 +0100 From: Oleg Nesterov To: Andrew Morton Cc: Benjamin Herrenschmidt , Roland McGrath , linux-kernel@vger.kernel.org Subject: [PATCH 3/5] ptrace: change tracehook_report_syscall_exit() to handle stepping Message-ID: <20091111213201.GA10653@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 Suggested by Roland. Change tracehook_report_syscall_exit() to look at step flag and send the trap signal if needed. This change affects ia64, microblaze, parisc, powerpc, sh. They pass nonzero "step" argument to tracehook but since it was ignored the tracee reports via ptrace_notify(), this is not right and not consistent. - PTRACE_SETSIGINFO doesn't work - if the tracer resumes the tracee with signr != 0 the new signal is generated rather than delivering it - If PT_TRACESYSGOOD is set the tracee reports the wrong exit_code I don't have a powerpc machine, but I think this test-case should see the difference: #include #include #include #include #include int main(void) { int pid, status; if (!(pid = fork())) { assert(ptrace(PTRACE_TRACEME) == 0); kill(getpid(), SIGSTOP); getppid(); return 0; } assert(pid == wait(&status)); assert(ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACESYSGOOD) == 0); assert(ptrace(PTRACE_SYSCALL, pid, 0,0) == 0); assert(pid == wait(&status)); assert(ptrace(PTRACE_SINGLESTEP, pid, 0,0) == 0); assert(pid == wait(&status)); if (status == 0x57F) return 0; printf("kernel bug: status=%X shouldn't have 0x80\n", status); return 1; } Signed-off-by: Oleg Nesterov Acked-by: Roland McGrath --- include/linux/tracehook.h | 7 +++++++ 1 file changed, 7 insertions(+) --- TH/include/linux/tracehook.h~3_TRACEHOOK_HANDLE_STEPPING 2009-11-10 01:03:22.000000000 +0100 +++ TH/include/linux/tracehook.h 2009-11-10 22:00:37.000000000 +0100 @@ -134,6 +134,13 @@ static inline __must_check int tracehook */ static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) { + if (step) { + siginfo_t info; + user_single_step_siginfo(current, regs, &info); + force_sig_info(SIGTRAP, &info, current); + return; + } + ptrace_report_syscall(regs); }