From 2ee5b92a2598d9e403337185fdf88f661dee8616 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 23 Jan 2018 13:25:04 -0500 Subject: [PATCH] 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) --- kernel/trace/trace.c | 34 +++++++++++--------- kernel/trace/trace_events_trigger.c | 13 ++++++-- kernel/trace/trace_functions.c | 49 +++++++++++++++++++++-------- 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 -- 2.30.2