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authorLi Zefan <lizf@cn.fujitsu.com>2009-06-24 09:52:58 +0800
committerIngo Molnar <mingo@elte.hu>2009-06-24 11:02:50 +0200
commitc8961ec6da22ea010bf4470a8e0fb3fdad0f11c4 (patch)
tree799b41a5eae2268010ca2d5b883a6c4fe33a9297 /kernel
parente1c7e2a6e67fe9db19dd15e71614526a31b5fdb1 (diff)
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: Lai Jiangshan <laijs@cn.fujitsu.com> Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li 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: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_printk.c26
1 files changed, 6 insertions, 20 deletions
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 9bece9687b6..7b627811082 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 = {