Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755383AbaDMS6z (ORCPT ); Sun, 13 Apr 2014 14:58:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41665 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754814AbaDMS6y (ORCPT ); Sun, 13 Apr 2014 14:58:54 -0400 Date: Sun, 13 Apr 2014 20:58:54 +0200 From: Oleg Nesterov To: Steven Rostedt Cc: Mathieu Desnoyers , Frederic Weisbecker , LKML , Andrew Morton , Ingo Molnar Subject: [PATCH v2 1/3] tracing: fix syscall_*regfunc() vs copy_process() race Message-ID: <20140413185854.GB20668@redhat.com> References: <1397059882-23063-3-git-send-email-fweisbec@gmail.com> <360091921.1294.1397060915052.JavaMail.zimbra@efficios.com> <20140409124249.4081e665@gandalf.local.home> <20140409170505.GA27638@redhat.com> <20140409170542.GB27638@redhat.com> <20140410090643.46ca2226@gandalf.local.home> <20140410133435.GB12228@redhat.com> <20140411112259.79f0a0ba@gandalf.local.home> <20140411155845.GA30199@redhat.com> <20140413185828.GA20668@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140413185828.GA20668@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() 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. Signed-off-by: Oleg Nesterov --- include/trace/syscall.h | 15 +++++++++++++++ kernel/fork.c | 2 ++ 2 files changed, 17 insertions(+), 0 deletions(-) diff --git a/include/trace/syscall.h b/include/trace/syscall.h index fed853f..291c282 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 a17621c..2d55a47 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1484,7 +1484,9 @@ 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) -- 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/