From: Ingo Molnar <mingo@elte.hu>
To: "Frédéric Weisbecker" <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] tracing/function-graph-tracer: prevent from hrtimer interrupt infinite loop
Date: Sun, 21 Dec 2008 11:00:47 +0100 [thread overview]
Message-ID: <20081221100047.GA31074@elte.hu> (raw)
In-Reply-To: <20081218214458.GA30834@elte.hu>
btw., a graph-tracer buglet i noticed:
3) | perf_counter_task_tick() {
3) | perf_counter_task_sched_out() {
3) | /* c:ffff88049b184000, u:0: 0000000020ca1ab0 + 0000000000000000 = 0000000020ca1ab0
*/
3) | /* sched-out counter ffff88049b184000, state: 0
*/
3) 5.024 us | }
3) | perf_counter_task_sched_in() {
3) | /* c:ffff88049b184000, u:0: 0000000020ca1ab0 + 0000000000000000 = 0000000020ca1ab0
*/
3) | /* sched-in counter ffff88049b184000, state: 1
*/
3) 2.605 us | }
3) 9.714 us | }
3) | perf_counter_task_tick() {
the bug is that the '*/' comment closing text is printed in the next line
- that's not a linewrap, it happened like this in the trace.
The reason is that the ftrace_printk did:
ftrace_printk("c:%p, u:%d: %016Lx + %016Lx = %016Lx\n",
the closing \n is pretty natural - especially for kernel hackers who might
just turn printk()s into ftrace_printk(), to embedd printouts in function
traces. So it would be nice if ftrace skipped over \n's when printing them
out as embedded C comments.
Ingo
next prev parent reply other threads:[~2008-12-21 10:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-18 1:09 [PATCH v2] tracing/function-graph-tracer: prevent from hrtimer interrupt infinite loop Frederic Weisbecker
2008-12-18 10:34 ` Ingo Molnar
2008-12-18 10:48 ` Thomas Gleixner
2008-12-18 10:56 ` Frédéric Weisbecker
2008-12-18 11:22 ` Ingo Molnar
2008-12-18 21:07 ` Frédéric Weisbecker
2008-12-18 21:16 ` Ingo Molnar
2008-12-18 21:36 ` Frédéric Weisbecker
2008-12-18 21:44 ` Ingo Molnar
2008-12-18 22:00 ` Frédéric Weisbecker
2008-12-21 10:00 ` Ingo Molnar [this message]
2008-12-21 10:12 ` Ingo Molnar
2008-12-21 12:21 ` Frédéric Weisbecker
2008-12-22 10:46 ` Frédéric Weisbecker
2008-12-18 10:51 ` Frédéric Weisbecker
2008-12-18 11:16 ` Ingo Molnar
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