[PATCH 5.14 518/849] samples/kretprobes: Fix return value if register_kretprobe() failed

Greg Kroah-Hartman
2021-11-15T23:06:39Z

From: Tiezhu Yang <yangtiezhu@loongson.cn>

[ Upstream commit f76fbbbb5061fe14824ba5807c44bd7400a6b4e1 ]

Use the actual return value instead of always -1 if register_kretprobe()
failed.

E.g. without this patch:

# insmod samples/kprobes/kretprobe_example.ko func=no_such_func
insmod: ERROR: could not insert module samples/kprobes/kretprobe_example.ko: Operation not permitted

With this patch:

# insmod samples/kprobes/kretprobe_example.ko func=no_such_func
insmod: ERROR: could not insert module samples/kprobes/kretprobe_example.ko: Unknown symbol in module

Link: https://lkml.kernel.org/r/1635213091-24387-2-git-send-email-yangtiezhu@loongson.cn

Fixes: 804defea1c02 ("Kprobes: move kprobe examples to samples/")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
samples/kprobes/kretprobe_example.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c
index 5dc1bf3baa98b..228321ecb1616 100644
--- a/samples/kprobes/kretprobe_example.c
+++ b/samples/kprobes/kretprobe_example.c
@@ -86,7 +86,7 @@ static int __init kretprobe_init(void)
ret = register_kretprobe(&my_kretprobe);
if (ret < 0) {
pr_err("register_kretprobe failed, returned %d\n", ret);
- return -1;
+ return ret;
}
pr_info("Planted return probe at %s: %p\n",
my_kretprobe.kp.symbol_name, my_kretprobe.kp.addr);
--
2.33.0