Merge tag 'trace-v5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Remove code I accidentally applied when doing a minor fix up to a
   patch, and then using "git commit -a --amend", which pulled in some
   other changes I was playing with.

 - Remove an used variable in trace_events_inject code

 - Fix function graph tracer when it traces a ftrace direct function.
   It will now ignore tracing a function that has a ftrace direct
   tramploine attached. This is needed for eBPF to use the ftrace direct
   code.

* tag 'trace-v5.5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix function_graph tracer interaction with BPF trampoline
  tracing: remove set but not used variable 'buffer'
  module: Remove accidental change of module_enable_x()

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 67e0c462b059..a2659735db73 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -101,6 +101,15 @@ int function_graph_enter(unsigned long ret, unsigned long func,
 {
 	struct ftrace_graph_ent trace;
 
+	/*
+	 * Skip graph tracing if the return location is served by direct trampoline,
+	 * since call sequence and return addresses is unpredicatable anymore.
+	 * Ex: BPF trampoline may call original function and may skip frame
+	 * depending on type of BPF programs attached.
+	 */
+	if (ftrace_direct_func_count &&
+	    ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE))
+		return -EBUSY;
 	trace.func = func;
 	trace.depth = ++current->curr_ret_depth;