From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sat, 20 Jun 2009 04:52:21 +0000 (+0200)
Subject: tracing/urgent: warn in case of ftrace_start_up inbalance
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9ea1a153a4fb435c22e9988784bb476671286112;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git

tracing/urgent: warn in case of ftrace_start_up inbalance

Prevent from further ftrace_start_up inbalances so that we avoid
future nop patching omissions with dynamic ftrace.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
---

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index bb60732ade0c..3718d55fb4c3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1224,6 +1224,13 @@ static void ftrace_shutdown(int command)
 		return;
 
 	ftrace_start_up--;
+	/*
+	 * Just warn in case of unbalance, no need to kill ftrace, it's not
+	 * critical but the ftrace_call callers may be never nopped again after
+	 * further ftrace uses.
+	 */
+	WARN_ON_ONCE(ftrace_start_up < 0);
+
 	if (!ftrace_start_up)
 		command |= FTRACE_DISABLE_CALLS;