Commit d82d6244 authored Jun 24, 2009 by Li Zefan Committed by Ingo Molnar Jun 24, 2009

ftrace: Fix t_hash_start()



When the output of set_ftrace_filter is larger than PAGE_SIZE,
t_hash_start() will be called the 2nd time, and then we start
from the head of a hlist, which is wrong and causes some entries
to be outputed twice.

The worse is, if the hlist is large enough, reading set_ftrace_filter
won't stop but in a dead loop.

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: <4A41876E.2060407@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 694ce0a5

kernel/trace/ftrace.c

+11 −1

Original line number	Diff line number	Diff line
		@@ -1417,10 +1417,20 @@ static void t_hash_start(struct seq_file m, loff_t *pos)
		{
		struct ftrace_iterator *iter = m->private;
		void *p = NULL;
		loff_t l;

		if (!(iter->flags & FTRACE_ITER_HASH))
		*pos = 0;

		iter->flags \|= FTRACE_ITER_HASH;

		return t_hash_next(m, p, pos);
		iter->hidx = 0;
		for (l = 0; l <= *pos; ) {
		p = t_hash_next(m, p, &l);
		if (!p)
		break;
		}
		return p;
		}

		static int t_hash_show(struct seq_file m, void v)