Merge tag 'trace-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Check for NULL in kretprobe_dispatcher()

   NULL can now be passed in, make sure it can handle it

 - Clean up unneeded #endif #ifdef of the same preprocessor
   check in the middle of the block.

 - Comment clean up

 - Remove unneeded initialization of the "ret" variable in
   __trace_uprobe_create()

* tag 'trace-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/uprobes: Remove unwanted initialization in __trace_uprobe_create()
  tracefs: Fix syntax errors in comments
  tracing: Simplify conditional compilation code in tracing_set_tracer()
  tracing/kprobes: Check whether get_kretprobe() returns NULL in kretprobe_dispatcher()

3 files changed, 10 insertions, 4 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2c95992e2c71..a8cfac0611bc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6424,9 +6424,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
 		synchronize_rcu();
 		free_snapshot(tr);
 	}
-#endif
 
-#ifdef CONFIG_TRACER_MAX_TRACE
 	if (t->use_max_tr && !had_max_tr) {
 		ret = tracing_alloc_snapshot_instance(tr);
 		if (ret < 0)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 93507330462c..a245ea673715 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1718,8 +1718,17 @@ static int
 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
 	struct kretprobe *rp = get_kretprobe(ri);
-	struct trace_kprobe *tk = container_of(rp, struct trace_kprobe, rp);
+	struct trace_kprobe *tk;
+
+	/*
+	 * There is a small chance that get_kretprobe(ri) returns NULL when
+	 * the kretprobe is unregister on another CPU between kretprobe's
+	 * trampoline_handler and this function.
+	 */
+	if (unlikely(!rp))
+		return 0;
 
+	tk = container_of(rp, struct trace_kprobe, rp);
 	raw_cpu_inc(*tk->nhit);
 
 	if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 9711589273cd..c3dc4f859a6b 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -546,7 +546,6 @@ static int __trace_uprobe_create(int argc, const char **argv)
 	bool is_return = false;
 	int i, ret;
 
-	ret = 0;
 	ref_ctr_offset = 0;
 
 	switch (argv[0][0]) {