From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756977AbaFSBmA (ORCPT ); Wed, 18 Jun 2014 21:42:00 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.229]:29902 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756931AbaFSBl7 (ORCPT ); Wed, 18 Jun 2014 21:41:59 -0400 Message-Id: <20140619014157.889720900@goodmis.org> User-Agent: quilt/0.63-1 Date: Wed, 18 Jun 2014 21:40:37 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Oleg Nesterov , Frederic Weisbecker Subject: [for-next][PATCH 1/3] tracing: Fix syscall_*regfunc() vs copy_process() race References: <20140619014036.116976241@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=0001-tracing-Fix-syscall_-regfunc-vs-copy_process-race.patch X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oleg Nesterov syscall_regfunc() and syscall_unregfunc() should set/clear TIF_SYSCALL_TRACEPOINT system-wide, but do_each_thread() can race with copy_process() and miss the new child which was not added to the process/thread lists yet. Change copy_process() to update the child's TIF_SYSCALL_TRACEPOINT under tasklist. Link: http://lkml.kernel.org/p/20140413185854.GB20668@redhat.com Cc: stable@vger.kernel.org # 2.6.33 Fixes: a871bd33a6c0 "tracing: Add syscall tracepoints" Acked-by: Frederic Weisbecker Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- include/trace/syscall.h | 15 +++++++++++++++ kernel/fork.c | 2 ++ 2 files changed, 17 insertions(+) diff --git a/include/trace/syscall.h b/include/trace/syscall.h index fed853f3d7aa..291c2824fafb 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -4,6 +4,7 @@ #include #include #include +#include #include @@ -32,4 +33,18 @@ struct syscall_metadata { struct ftrace_event_call *exit_event; }; +#ifdef CONFIG_TRACEPOINTS +static inline void syscall_tracepoint_update(struct task_struct *p) +{ + if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) + set_tsk_thread_flag(p, TIF_SYSCALL_TRACEPOINT); + else + clear_tsk_thread_flag(p, TIF_SYSCALL_TRACEPOINT); +} +#else +static inline void syscall_tracepoint_update(struct task_struct *p) +{ +} +#endif + #endif /* _TRACE_SYSCALL_H */ diff --git a/kernel/fork.c b/kernel/fork.c index d2799d1fc952..6a13c46cd87d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1487,7 +1487,9 @@ static struct task_struct *copy_process(unsigned long clone_flags, total_forks++; spin_unlock(¤t->sighand->siglock); + syscall_tracepoint_update(p); write_unlock_irq(&tasklist_lock); + proc_fork_connector(p); cgroup_post_fork(p); if (clone_flags & CLONE_THREAD) -- 2.0.0.rc2