scripts/tracing: fix the bug that can't parse raw_trace_func

Since commit 77271ce4b2 ("tracing: Add irq, preempt-count and need resched info
to default trace output"), the default trace output format has been changed to:
          <idle>-0       [009] d.h. 22420.068695: _raw_spin_lock_irqsave <-hrtimer_interrupt
          <idle>-0       [000] ..s. 22420.068695: _nohz_idle_balance <-run_rebalance_domains
          <idle>-0       [011] d.h. 22420.068695: account_process_tick <-update_process_times

origin trace output format:(before v3.2.0)
     # tracer: nop
     #
     #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
     #              | |       |          |         |
          migration/0-6     [000]    50.025810: rcu_note_context_switch <-__schedule
          migration/0-6     [000]    50.025812: trace_rcu_utilization <-rcu_note_context_switch
          migration/0-6     [000]    50.025813: rcu_sched_qs <-rcu_note_context_switch
          migration/0-6     [000]    50.025815: rcu_preempt_qs <-rcu_note_context_switch
          migration/0-6     [000]    50.025817: trace_rcu_utilization <-rcu_note_context_switch
          migration/0-6     [000]    50.025818: debug_lockdep_rcu_enabled <-__schedule
          migration/0-6     [000]    50.025820: debug_lockdep_rcu_enabled <-__schedule

The draw_functrace.py(introduced in v2.6.28) can't parse the new version format trace_func,
So we need modify draw_functrace.py to adapt the new version trace output format.

Link: https://lkml.kernel.org/r/20210611022107.608787-1-suhui@zeku.com

Cc: stable@vger.kernel.org
Fixes: 77271ce4b2 tracing: Add irq, preempt-count and need resched info to default trace output
Signed-off-by: Hui Su <suhui@zeku.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

scripts/tracing/draw_functrace.py

@@ -17,7 +17,7 @@ Usage:
 	$ cat /sys/kernel/debug/tracing/trace_pipe > ~/raw_trace_func
 	Wait some times but not too much, the script is a bit slow.
 	Break the pipe (Ctrl + Z)
-	$ scripts/draw_functrace.py < raw_trace_func > draw_functrace
+	$ scripts/tracing/draw_functrace.py < ~/raw_trace_func > draw_functrace
 	Then you have your drawn trace in draw_functrace
 """
 
@@ -103,10 +103,10 @@ def parseLine(line):
 	line = line.strip()
 	if line.startswith("#"):
 		raise CommentLineException
-	m = re.match("[^]]+?\\] +([0-9.]+): (\\w+) <-(\\w+)", line)
+	m = re.match("[^]]+?\\] +([a-z.]+) +([0-9.]+): (\\w+) <-(\\w+)", line)
 	if m is None:
 		raise BrokenLineException
-	return (m.group(1), m.group(2), m.group(3))
+	return (m.group(2), m.group(3), m.group(4))
 
 
 def main():