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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2018-01-23 21:25:04 +0300
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-01-23 23:57:00 +0300
commit2ee5b92a2598d9e403337185fdf88f661dee8616 (patch)
tree39672f39ff98d7fc2fea7b59467e76c4609ecfc2 /kernel/trace
parent6be7fa3c74d1e0cd50f2157b5c1524f152bf641e (diff)
downloadlinux-2ee5b92a2598d9e403337185fdf88f661dee8616.tar.xz
tracing: Update stack trace skipping for ORC unwinder
With the addition of ORC unwinder and FRAME POINTER unwinder, the stack trace skipping requirements have changed. I went through the tracing stack trace dumps with ORC and with frame pointers and recalculated the proper values. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c34
-rw-r--r--kernel/trace/trace_events_trigger.c13
-rw-r--r--kernel/trace/trace_functions.c49
3 files changed, 67 insertions, 29 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a8d8a294345..8e3f20a18a06 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2374,6 +2374,15 @@ void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
}
EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
+/*
+ * Skip 3:
+ *
+ * trace_buffer_unlock_commit_regs()
+ * trace_event_buffer_commit()
+ * trace_event_raw_event_xxx()
+*/
+# define STACK_SKIP 3
+
void trace_buffer_unlock_commit_regs(struct trace_array *tr,
struct ring_buffer *buffer,
struct ring_buffer_event *event,
@@ -2383,16 +2392,12 @@ void trace_buffer_unlock_commit_regs(struct trace_array *tr,
__buffer_unlock_commit(buffer, event);
/*
- * If regs is not set, then skip the following callers:
- * trace_buffer_unlock_commit_regs
- * event_trigger_unlock_commit
- * trace_event_buffer_commit
- * trace_event_raw_event_sched_switch
+ * If regs is not set, then skip the necessary functions.
* Note, we can still get here via blktrace, wakeup tracer
* and mmiotrace, but that's ok if they lose a function or
- * two. They are that meaningful.
+ * two. They are not that meaningful.
*/
- ftrace_trace_stack(tr, buffer, flags, regs ? 0 : 4, pc, regs);
+ ftrace_trace_stack(tr, buffer, flags, regs ? 0 : STACK_SKIP, pc, regs);
ftrace_trace_userstack(buffer, flags, pc);
}
@@ -2579,11 +2584,13 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer,
trace.skip = skip;
/*
- * Add two, for this function and the call to save_stack_trace()
+ * Add one, for this function and the call to save_stack_trace()
* If regs is set, then these functions will not be in the way.
*/
+#ifndef CONFIG_UNWINDER_ORC
if (!regs)
- trace.skip += 2;
+ trace.skip++;
+#endif
/*
* Since events can happen in NMIs there's no safe way to
@@ -2711,11 +2718,10 @@ void trace_dump_stack(int skip)
local_save_flags(flags);
- /*
- * Skip 3 more, seems to get us at the caller of
- * this function.
- */
- skip += 3;
+#ifndef CONFIG_UNWINDER_ORC
+ /* Skip 1 to skip this function. */
+ skip++;
+#endif
__ftrace_trace_stack(global_trace.trace_buffer.buffer,
flags, skip, preempt_count(), NULL);
}
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index f2ac9d44f6c4..87411482a46f 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -1123,13 +1123,22 @@ static __init int register_trigger_snapshot_cmd(void) { return 0; }
#endif /* CONFIG_TRACER_SNAPSHOT */
#ifdef CONFIG_STACKTRACE
+#ifdef CONFIG_UNWINDER_ORC
+/* Skip 2:
+ * event_triggers_post_call()
+ * trace_event_raw_event_xxx()
+ */
+# define STACK_SKIP 2
+#else
/*
- * Skip 3:
+ * Skip 4:
* stacktrace_trigger()
* event_triggers_post_call()
+ * trace_event_buffer_commit()
* trace_event_raw_event_xxx()
*/
-#define STACK_SKIP 3
+#define STACK_SKIP 4
+#endif
static void
stacktrace_trigger(struct event_trigger_data *data, void *rec)
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 27f7ad12c4b1..b611cd36e22d 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -154,6 +154,24 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
preempt_enable_notrace();
}
+#ifdef CONFIG_UNWINDER_ORC
+/*
+ * Skip 2:
+ *
+ * function_stack_trace_call()
+ * ftrace_call()
+ */
+#define STACK_SKIP 2
+#else
+/*
+ * Skip 3:
+ * __trace_stack()
+ * function_stack_trace_call()
+ * ftrace_call()
+ */
+#define STACK_SKIP 3
+#endif
+
static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
@@ -180,15 +198,7 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
if (likely(disabled == 1)) {
pc = preempt_count();
trace_function(tr, ip, parent_ip, flags, pc);
- /*
- * skip over 5 funcs:
- * __ftrace_trace_stack,
- * __trace_stack,
- * function_stack_trace_call
- * ftrace_list_func
- * ftrace_call
- */
- __trace_stack(tr, flags, 5, pc);
+ __trace_stack(tr, flags, STACK_SKIP, pc);
}
atomic_dec(&data->disabled);
@@ -367,14 +377,27 @@ ftrace_traceoff(unsigned long ip, unsigned long parent_ip,
tracer_tracing_off(tr);
}
+#ifdef CONFIG_UNWINDER_ORC
/*
- * Skip 4:
+ * Skip 3:
+ *
+ * function_trace_probe_call()
+ * ftrace_ops_assist_func()
+ * ftrace_call()
+ */
+#define FTRACE_STACK_SKIP 3
+#else
+/*
+ * Skip 5:
+ *
+ * __trace_stack()
* ftrace_stacktrace()
* function_trace_probe_call()
- * ftrace_ops_list_func()
+ * ftrace_ops_assist_func()
* ftrace_call()
*/
-#define STACK_SKIP 4
+#define FTRACE_STACK_SKIP 5
+#endif
static __always_inline void trace_stack(struct trace_array *tr)
{
@@ -384,7 +407,7 @@ static __always_inline void trace_stack(struct trace_array *tr)
local_save_flags(flags);
pc = preempt_count();
- __trace_stack(tr, flags, STACK_SKIP, pc);
+ __trace_stack(tr, flags, FTRACE_STACK_SKIP, pc);
}
static void