From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753402AbdBCNmV (ORCPT ); Fri, 3 Feb 2017 08:42:21 -0500 Received: from mail.kernel.org ([198.145.29.136]:53982 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753250AbdBCNlm (ORCPT ); Fri, 3 Feb 2017 08:41:42 -0500 Message-Id: <20170203134137.445198321@goodmis.org> User-Agent: quilt/0.63-1 Date: Fri, 03 Feb 2017 08:40:38 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Namhyung Kim Subject: [for-next][PATCH 5/8] ftrace: Have set_graph_functions handle write with RDWR References: <20170203134033.087760237@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0005-ftrace-Have-set_graph_functions-handle-write-with-RD.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" Since reading the set_graph_functions uses seq functions, which sets the file->private_data pointer to a seq_file descriptor. On writes the ftrace_graph_data descriptor is set to file->private_data. But if the file is opened for RDWR, the ftrace_graph_write() will incorrectly use the file->private_data descriptor instead of ((struct seq_file *)file->private_data)->private pointer, and this can crash the kernel. Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b7df0dcf8652..0233c8cb45f4 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4842,6 +4842,12 @@ ftrace_graph_write(struct file *file, const char __user *ubuf, if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) return -ENOMEM; + /* Read mode uses seq functions */ + if (file->f_mode & FMODE_READ) { + struct seq_file *m = file->private_data; + fgd = m->private; + } + read = trace_get_user(&parser, ubuf, cnt, ppos); if (read >= 0 && trace_parser_loaded((&parser))) { -- 2.10.2