From 2ee5b92a2598d9e403337185fdf88f661dee8616 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 23 Jan 2018 13:25:04 -0500 Subject: 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 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-) (limited to 'kernel/trace/trace.c') 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); } -- cgit v1.2.3