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Commit c8961ec6 authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

tracing_bprintk: Don't increment @pos in t_start() 



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.

Reported-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: default avatarLiming Wang <liming.wang@windriver.com>
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A4186FA.1020106@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e1c7e2a6

kernel/trace/trace_printk.c

+6 −20
Original line number Diff line number Diff line
@@ -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 = {