All of lore.kernel.org
 help / color / mirror / Atom feed
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCH 2/2] tracing/urgent: warn in case of ftrace_start_up inbalance
Date: Sat, 20 Jun 2009 07:06:12 +0200	[thread overview]
Message-ID: <1245474372-5249-3-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1245474372-5249-1-git-send-email-fweisbec@gmail.com>

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>
---
 kernel/trace/ftrace.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index bb60732..3718d55 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;
 
-- 
1.6.2.3


  parent reply	other threads:[~2009-06-20  5:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-20  5:06 [PATCH 0/2] tracing/urgent: fixes for nop patching omissions Frederic Weisbecker
2009-06-20  5:06 ` [PATCH 1/2] tracing/urgent: fix unbalanced ftrace_start_up Frederic Weisbecker
2009-06-20  5:06 ` Frederic Weisbecker [this message]
2009-06-20 15:11 ` [PATCH 0/2] tracing/urgent: fixes for nop patching omissions Ingo Molnar

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1245474372-5249-3-git-send-email-fweisbec@gmail.com \
    --to=fweisbec@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=rostedt@goodmis.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.