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ftrace,kdb: Extend kdb to be able to dump the ftrace buffer

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Add in a helper function to allow the kdb shell to dump the ftrace
buffer.

Modify trace.c to expose the capability to iterate over the ftrace
buffer in a read only capacity.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Jason Wessel
2010-08-05 09:22:23 -05:00
parent 3f0a55e357
commit 955b61e597
4 changed files with 163 additions and 21 deletions
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43
kernel/trace/trace.c
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@@ -101,10 +101,7 @@ static inline void ftrace_enable_cpu(void)
preempt_enable();
}
static cpumask_var_t __read_mostly tracing_buffer_mask;
#define for_each_tracing_cpu(cpu) \
for_each_cpu(cpu, tracing_buffer_mask)
cpumask_var_t __read_mostly tracing_buffer_mask;
/*
* ftrace_dump_on_oops - variable to dump ftrace buffer on oops
@@ -1539,11 +1536,6 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
}
EXPORT_SYMBOL_GPL(trace_vprintk);
enum trace_file_type {
TRACE_FILE_LAT_FMT = 1,
TRACE_FILE_ANNOTATE = 2,
};
static void trace_iterator_increment(struct trace_iterator *iter)
{
/* Don't allow ftrace to trace into the ring buffers */
@@ -1641,7 +1633,7 @@ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
}
/* Find the next real entry, and increment the iterator to the next entry */
static void *find_next_entry_inc(struct trace_iterator *iter)
void *trace_find_next_entry_inc(struct trace_iterator *iter)
{
iter->ent = __find_next_entry(iter, &iter->cpu,
&iter->lost_events, &iter->ts);
@@ -1676,19 +1668,19 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos)
return NULL;
if (iter->idx < 0)
ent = find_next_entry_inc(iter);
ent = trace_find_next_entry_inc(iter);
else
ent = iter;
while (ent && iter->idx < i)
ent = find_next_entry_inc(iter);
ent = trace_find_next_entry_inc(iter);
iter->pos = *pos;
return ent;
}
static void tracing_iter_reset(struct trace_iterator *iter, int cpu)
void tracing_iter_reset(struct trace_iterator *iter, int cpu)
{
struct trace_array *tr = iter->tr;
struct ring_buffer_event *event;
@@ -2049,7 +2041,7 @@ int trace_empty(struct trace_iterator *iter)
}
/* Called with trace_event_read_lock() held. */
static enum print_line_t print_trace_line(struct trace_iterator *iter)
enum print_line_t print_trace_line(struct trace_iterator *iter)
{
enum print_line_t ret;
@@ -3211,7 +3203,7 @@ waitagain:
trace_event_read_lock();
trace_access_lock(iter->cpu_file);
while (find_next_entry_inc(iter) != NULL) {
while (trace_find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
int len = iter->seq.len;
@@ -3294,7 +3286,7 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
if (ret != TRACE_TYPE_NO_CONSUME)
trace_consume(iter);
rem -= count;
if (!find_next_entry_inc(iter)) {
if (!trace_find_next_entry_inc(iter)) {
rem = 0;
iter->ent = NULL;
break;
@@ -3350,7 +3342,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
if (ret <= 0)
goto out_err;
if (!iter->ent && !find_next_entry_inc(iter)) {
if (!iter->ent && !trace_find_next_entry_inc(iter)) {
ret = -EFAULT;
goto out_err;
}
@@ -4414,7 +4406,7 @@ static struct notifier_block trace_die_notifier = {
*/
#define KERN_TRACE KERN_EMERG
static void
void
trace_printk_seq(struct trace_seq *s)
{
/* Probably should print a warning here. */
@@ -4429,6 +4421,13 @@ trace_printk_seq(struct trace_seq *s)
trace_seq_init(s);
}
void trace_init_global_iter(struct trace_iterator *iter)
{
iter->tr = &global_trace;
iter->trace = current_trace;
iter->cpu_file = TRACE_PIPE_ALL_CPU;
}
static void
__ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
{
@@ -4454,8 +4453,10 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
if (disable_tracing)
ftrace_kill();
trace_init_global_iter(&iter);
for_each_tracing_cpu(cpu) {
atomic_inc(&global_trace.data[cpu]->disabled);
atomic_inc(&iter.tr->data[cpu]->disabled);
}
old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
@@ -4504,7 +4505,7 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
iter.iter_flags |= TRACE_FILE_LAT_FMT;
iter.pos = -1;
if (find_next_entry_inc(&iter) != NULL) {
if (trace_find_next_entry_inc(&iter) != NULL) {
int ret;
ret = print_trace_line(&iter);
@@ -4526,7 +4527,7 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
trace_flags |= old_userobj;
for_each_tracing_cpu(cpu) {
atomic_dec(&global_trace.data[cpu]->disabled);
atomic_dec(&iter.tr->data[cpu]->disabled);
}
tracing_on();
}