From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753973Ab2DAVic (ORCPT ); Sun, 1 Apr 2012 17:38:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:65383 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753132Ab2DAVib (ORCPT ); Sun, 1 Apr 2012 17:38:31 -0400 Date: Sun, 1 Apr 2012 23:38:19 +0200 From: Oleg Nesterov To: Steven Rostedt Cc: Ingo Molnar , Jason Baron , linux-kernel@vger.kernel.org, Hendrik Brueckner , Frederic Weisbecker Subject: [PATCH 2/2] tracing: syscall_regfunc() should not skip kernel threads Message-ID: <20120401213819.GC17795@redhat.com> References: <20120330183104.GA12927@redhat.com> <1333134131.23924.191.camel@gandalf.stny.rr.com> <20120330201550.GA16628@redhat.com> <1333152806.23924.196.camel@gandalf.stny.rr.com> <20120331204501.GA18572@redhat.com> <1333229859.23924.200.camel@gandalf.stny.rr.com> <20120401213748.GA17795@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120401213748.GA17795@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 syscall_regfunc() ignores the kernel thread because "it has no effect", see cc3b13c1 "Don't trace kernel thread syscalls". However, this means that a user-space task spawned by call_usermodehelper() won't report the system calls if kernel_execve() is called when sys_tracepoint_refcount != 0. Remove this check. Hopefully the unnecessary report from ret_from_fork path mentioned by cc3b13c1 is fine. In fact "this is the only case" is not true. Say, kernel_execve() itself does "int 80" on X86_32. Hopefully fine too. Signed-off-by: Oleg Nesterov --- kernel/tracepoint.c | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index e2a4523..2403e60 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -739,9 +739,7 @@ void syscall_regfunc(void) if (!sys_tracepoint_refcount) { read_lock(&tasklist_lock); do_each_thread(g, t) { - /* Skip kernel threads. */ - if (!(t->flags & PF_KTHREAD)) - set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); + set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); } while_each_thread(g, t); read_unlock(&tasklist_lock); } -- 1.5.5.1