Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030830AbaGDWYA (ORCPT ); Fri, 4 Jul 2014 18:24:00 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57777 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760877AbaGDWXL (ORCPT ); Fri, 4 Jul 2014 18:23:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Frederic Weisbecker , "Paul E. McKenney" , Oleg Nesterov , Steven Rostedt Subject: [PATCH 3.10 45/46] tracing: Fix syscall_*regfunc() vs copy_process() race Date: Fri, 4 Jul 2014 15:19:49 -0700 Message-Id: <20140704221604.342503985@linuxfoundation.org> X-Mailer: git-send-email 2.0.1 In-Reply-To: <20140704221602.280733370@linuxfoundation.org> References: <20140704221602.280733370@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov commit 4af4206be2bd1933cae20c2b6fb2058dbc887f7c upstream. 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 Fixes: a871bd33a6c0 "tracing: Add syscall tracepoints" Acked-by: Frederic Weisbecker Acked-by: Paul E. McKenney Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- include/trace/syscall.h | 15 +++++++++++++++ kernel/fork.c | 2 ++ 2 files changed, 17 insertions(+) --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -4,6 +4,7 @@ #include #include #include +#include #include @@ -31,4 +32,18 @@ struct syscall_metadata { struct ftrace_event_call *exit_event; }; +#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_HAVE_SYSCALL_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 */ --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1479,7 +1479,9 @@ static struct task_struct *copy_process( 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) -- 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/