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()

3 files changed, 16 insertions, 14 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;
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 74439ab5c2b6..ac99a3500076 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2364,7 +2364,7 @@ int ftrace_direct_func_count;
  * Search the direct_functions hash to see if the given instruction pointer
  * has a direct caller attached to it.
  */
-static unsigned long find_rec_direct(unsigned long ip)
+unsigned long ftrace_find_rec_direct(unsigned long ip)
 {
 	struct ftrace_func_entry *entry;
 
@@ -2380,7 +2380,7 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip,
 {
 	unsigned long addr;
 
-	addr = find_rec_direct(ip);
+	addr = ftrace_find_rec_direct(ip);
 	if (!addr)
 		return;
 
@@ -2393,11 +2393,6 @@ struct ftrace_ops direct_ops = {
 			  | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
 			  | FTRACE_OPS_FL_PERMANENT,
 };
-#else
-static inline unsigned long find_rec_direct(unsigned long ip)
-{
-	return 0;
-}
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 /**
@@ -2417,7 +2412,7 @@ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
 
 	if ((rec->flags & FTRACE_FL_DIRECT) &&
 	    (ftrace_rec_count(rec) == 1)) {
-		addr = find_rec_direct(rec->ip);
+		addr = ftrace_find_rec_direct(rec->ip);
 		if (addr)
 			return addr;
 		WARN_ON_ONCE(1);
@@ -2458,7 +2453,7 @@ unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
 
 	/* Direct calls take precedence over trampolines */
 	if (rec->flags & FTRACE_FL_DIRECT_EN) {
-		addr = find_rec_direct(rec->ip);
+		addr = ftrace_find_rec_direct(rec->ip);
 		if (addr)
 			return addr;
 		WARN_ON_ONCE(1);
@@ -3604,7 +3599,7 @@ static int t_show(struct seq_file *m, void *v)
 		if (rec->flags & FTRACE_FL_DIRECT) {
 			unsigned long direct;
 
-			direct = find_rec_direct(rec->ip);
+			direct = ftrace_find_rec_direct(rec->ip);
 			if (direct)
 				seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
 		}
@@ -5008,7 +5003,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
 	mutex_lock(&direct_mutex);
 
 	/* See if there's a direct function at @ip already */
-	if (find_rec_direct(ip))
+	if (ftrace_find_rec_direct(ip))
 		goto out_unlock;
 
 	ret = -ENODEV;
@@ -5027,7 +5022,7 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
 	if (ip != rec->ip) {
 		ip = rec->ip;
 		/* Need to check this ip for a direct. */
-		if (find_rec_direct(ip))
+		if (ftrace_find_rec_direct(ip))
 			goto out_unlock;
 	}
 
diff --git a/kernel/trace/trace_events_inject.c b/kernel/trace/trace_events_inject.c
index d43710718ee5..d45079ee62f8 100644
--- a/kernel/trace/trace_events_inject.c
+++ b/kernel/trace/trace_events_inject.c
@@ -17,12 +17,10 @@ static int
 trace_inject_entry(struct trace_event_file *file, void *rec, int len)
 {
 	struct trace_event_buffer fbuffer;
-	struct ring_buffer *buffer;
 	int written = 0;
 	void *entry;
 
 	rcu_read_lock_sched();
-	buffer = file->tr->trace_buffer.buffer;
 	entry = trace_event_buffer_reserve(&fbuffer, file, len);
 	if (entry) {
 		memcpy(entry, rec, len);