From: Ingo Molnar <mingo@elte.hu>
Date: Sat, 8 Nov 2008 08:34:35 +0000 (+0100)
Subject: Merge branches 'tracing/ftrace', 'tracing/fastboot', 'tracing/nmisafe' and 'tracing... 
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a6b0786f7f83bcc4d414a2977aaebe2941ebe1de;p=mv-sheeva.git

Merge branches 'tracing/ftrace', 'tracing/fastboot', 'tracing/nmisafe' and 'tracing/urgent' into tracing/core
---

a6b0786f7f83bcc4d414a2977aaebe2941ebe1de
diff --cc include/linux/ftrace.h
index 7a75fc6d41f,1b340e3fa24,703eb53cfa2..1f5608c1102
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@@@ -214,11 -182,8 -181,6 +212,11 @@@@ static inline void __ftrace_enabled_res
   #endif
   
   #ifdef CONFIG_TRACING
  +extern int ftrace_dump_on_oops;
  +
 ++extern void tracing_start(void);
 ++extern void tracing_stop(void);
 ++
   extern void
   ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
   
diff --cc kernel/trace/ring_buffer.c
index a2dea500882,cedf4e26828,3f338063864..6781e9aab2c
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@@@ -1526,11 -1532,10 -1547,23 +1541,24 @@@@ rb_get_reader_page(struct ring_buffer_p
   {
   	struct buffer_page *reader = NULL;
   	unsigned long flags;
++ 	int nr_loops = 0;
   
 --	spin_lock_irqsave(&cpu_buffer->lock, flags);
 ++	local_irq_save(flags);
 ++	__raw_spin_lock(&cpu_buffer->lock);
   
    again:
++ 	/*
++ 	 * This should normally only loop twice. But because the
++ 	 * start of the reader inserts an empty page, it causes
++ 	 * a case where we will loop three times. There should be no
++ 	 * reason to loop four times (that I know of).
++ 	 */
++ 	if (unlikely(++nr_loops > 3)) {
++ 		RB_WARN_ON(cpu_buffer, 1);
++ 		reader = NULL;
++ 		goto out;
++ 	}
++ 
   	reader = cpu_buffer->reader_page;
   
   	/* If there's more to read, return this page */
diff --cc kernel/trace/trace.c
index ff1e9ed9b58,e4c40c868d6,974973e39e8..d55ccfc8d67
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@@@ -71,36 -62,38 -62,7 +71,36 @@@@ static cpumask_t __read_mostly		tracing
   #define for_each_tracing_cpu(cpu)	\
   	for_each_cpu_mask(cpu, tracing_buffer_mask)
   
 --static int tracing_disabled = 1;
 - 
  +/*
  + * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
  + *
  + * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
  + * is set, then ftrace_dump is called. This will output the contents
  + * of the ftrace buffers to the console.  This is very useful for
  + * capturing traces that lead to crashes and outputing it to a
  + * serial console.
  + *
  + * It is default off, but you can enable it with either specifying
  + * "ftrace_dump_on_oops" in the kernel command line, or setting
  + * /proc/sys/kernel/ftrace_dump_on_oops to true.
  + */
  +int ftrace_dump_on_oops;
  +
  +static int tracing_set_tracer(char *buf);
  +
  +static int __init set_ftrace(char *str)
  +{
  +	tracing_set_tracer(str);
  +	return 1;
  +}
  +__setup("ftrace", set_ftrace);
  +
  +static int __init set_ftrace_dump_on_oops(char *str)
  +{
  +	ftrace_dump_on_oops = 1;
  +	return 1;
  +}
  +__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
   
   long
   ns2usecs(cycle_t nsec)