From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753592AbZFXBwT (ORCPT ); Tue, 23 Jun 2009 21:52:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752751AbZFXBwD (ORCPT ); Tue, 23 Jun 2009 21:52:03 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:64966 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751180AbZFXBwC (ORCPT ); Tue, 23 Jun 2009 21:52:02 -0400 Message-ID: <4A4186FA.1020106@cn.fujitsu.com> Date: Wed, 24 Jun 2009 09:52:58 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Ingo Molnar CC: Steven Rostedt , Frederic Weisbecker , Liming Wang , LKML , Lai Jiangshan Subject: [PATCH 2/7] tracing_bprintk: don't increment @pos in t_start() References: <4A4186C6.9090706@cn.fujitsu.com> In-Reply-To: <4A4186C6.9090706@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It's wrong to increment @pos in t_start(), otherwise we'll lose some entries when reading printk_formats, if the output is larger than PAGE_SIZE. [ Impact: fix missing entries when reading printk_formats ] Reported-by: Lai Jiangshan Reviewed-by: Liming Wang Signed-off-by: Li Zefan --- kernel/trace/trace_printk.c | 26 ++++++-------------------- 1 files changed, 6 insertions(+), 20 deletions(-) diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c index 9bece96..7b62781 100644 --- a/kernel/trace/trace_printk.c +++ b/kernel/trace/trace_printk.c @@ -155,25 +155,19 @@ int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap) EXPORT_SYMBOL_GPL(__ftrace_vprintk); static void * -t_next(struct seq_file *m, void *v, loff_t *pos) +t_start(struct seq_file *m, loff_t *pos) { - const char **fmt = m->private; - const char **next = fmt; - - (*pos)++; + const char **fmt = __start___trace_bprintk_fmt + *pos; if ((unsigned long)fmt >= (unsigned long)__stop___trace_bprintk_fmt) return NULL; - - next = fmt; - m->private = ++next; - return fmt; } -static void *t_start(struct seq_file *m, loff_t *pos) +static void *t_next(struct seq_file *m, void * v, loff_t *pos) { - return t_next(m, NULL, pos); + (*pos)++; + return t_start(m, pos); } static int t_show(struct seq_file *m, void *v) @@ -224,15 +218,7 @@ static const struct seq_operations show_format_seq_ops = { static int ftrace_formats_open(struct inode *inode, struct file *file) { - int ret; - - ret = seq_open(file, &show_format_seq_ops); - if (!ret) { - struct seq_file *m = file->private_data; - - m->private = __start___trace_bprintk_fmt; - } - return ret; + return seq_open(file, &show_format_seq_ops); } static const struct file_operations ftrace_formats_fops = { -- 1.5.4.rc3