[PATCH -tip v8 12/13] tracing: Show kretprobe unknown indicator only for kretprobe_trampoline

Masami Hiramatsu
2021-06-18T07:07:17Z

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

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Andrii Nakryik <andrii@kernel.org>
---
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 d0368a569bfa..e46780670742 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);