From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Tue, 14 Sep 2021 23:42:40 +0900
Subject: tracing: Show kretprobe unknown indicator only for
 kretprobe_trampoline
Git-commit: 7da89495d500d6a1e6fe1019587c3b611c7bd217
Patch-mainline: v5.16-rc1
References: bsc#1193277

ftrace shows "[unknown/kretprobe'd]" indicator all addresses in the
kretprobe_trampoline, but the modified address by kretprobe should
be only kretprobe_trampoline+0.

Link: https://lkml.kernel.org/r/163163056044.489837.794883849706638013.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
---
 kernel/trace/trace_output.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 5a5949c659d0..3547e7176ff7 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -8,6 +8,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ftrace.h>
+#include <linux/kprobes.h>
 #include <linux/sched/clock.h>
 #include <linux/sched/mm.h>
 
@@ -346,22 +347,12 @@ int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
 }
 EXPORT_SYMBOL_GPL(trace_output_call);
 
-#ifdef CONFIG_KRETPROBES
-static inline const char *kretprobed(const char *name)
+static inline const char *kretprobed(const char *name, unsigned long addr)
 {
-	static const char tramp_name[] = "__kretprobe_trampoline";
-	int size = sizeof(tramp_name);
-
-	if (strncmp(tramp_name, name, size) == 0)
+	if (is_kretprobe_trampoline(addr))
 		return "[unknown/kretprobe'd]";
 	return name;
 }
-#else
-static inline const char *kretprobed(const char *name)
-{
-	return name;
-}
-#endif /* CONFIG_KRETPROBES */
 
 void
 trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset)
@@ -374,7 +365,7 @@ trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset)
 		sprint_symbol(str, address);
 	else
 		kallsyms_lookup(address, NULL, NULL, NULL, str);
-	name = kretprobed(str);
+	name = kretprobed(str, address);
 
 	if (name && strlen(name)) {
 		trace_seq_puts(s, name);