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Commit dcc19d28 authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
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tracing/ftrace: Allow for instances to trigger their own stacktrace probes 



Have the stacktrace function trigger probe trigger stack traces within the
instance that they were added to in the set_ftrace_filter.

 ># cd /sys/kernel/debug/tracing
 ># mkdir instances/foo
 ># cd instances/foo
 ># echo schedule:stacktrace:1 > set_ftrace_filter
 ># cat trace
 # tracer: nop
 #
 # entries-in-buffer/entries-written: 1/1   #P:4
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
           <idle>-0     [001] .N.2   202.585010: <stack trace>
  =>
  => schedule
  => schedule_preempt_disabled
  => do_idle
  => cpu_startup_entry
  => start_secondary
  => verify_cpu

Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 2290f2c5

kernel/trace/trace_functions.c

+14 −3
Original line number Diff line number Diff line
@@ -375,12 +375,23 @@ ftrace_traceoff(unsigned long ip, unsigned long parent_ip, 
 */

#define STACK_SKIP 4



static __always_inline void trace_stack(struct trace_array *tr)

{

	unsigned long flags;

	int pc;



	local_save_flags(flags);

	pc = preempt_count();



	__trace_stack(tr, flags, STACK_SKIP, pc);

}



static void

ftrace_stacktrace(unsigned long ip, unsigned long parent_ip,

		  struct trace_array *tr, struct ftrace_probe_ops *ops,

		  void *data)

{

	trace_dump_stack(STACK_SKIP);

	trace_stack(tr);

}



static void
@@ -398,7 +409,7 @@ ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, 


	/* unlimited? */

	if (!mapper) {

		trace_dump_stack(STACK_SKIP);

		trace_stack(tr);

		return;

	}
@@ -417,7 +428,7 @@ ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, 
		new_count = old_count - 1;

		new_count = cmpxchg(count, old_count, new_count);

		if (new_count == old_count)

			trace_dump_stack(STACK_SKIP);

			trace_stack(tr);



		if (!tracing_is_on())

			return;