diff options
Diffstat (limited to 'samples/kprobes/kretprobe_example.c')
| -rw-r--r-- | samples/kprobes/kretprobe_example.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c index 7f9060f435cd..65d6dcafd742 100644 --- a/samples/kprobes/kretprobe_example.c +++ b/samples/kprobes/kretprobe_example.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * kretprobe_example.c * @@ -7,10 +8,10 @@ * * usage: insmod kretprobe_example.ko func=<func_name> * - * If no func_name is specified, _do_fork is instrumented + * If no func_name is specified, kernel_clone is instrumented * * For more information on theory of operation of kretprobes, see - * Documentation/kprobes.txt + * Documentation/trace/kprobes.rst * * Build and insert the kernel module as done in the kprobe example. * You will see the trace data in /var/log/messages and on the console @@ -22,11 +23,10 @@ #include <linux/module.h> #include <linux/kprobes.h> #include <linux/ktime.h> -#include <linux/limits.h> #include <linux/sched.h> -static char func_name[NAME_MAX] = "_do_fork"; -module_param_string(func, func_name, NAME_MAX, S_IRUGO); +static char func_name[KSYM_NAME_LEN] = "kernel_clone"; +module_param_string(func, func_name, KSYM_NAME_LEN, 0644); MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the" " function's execution time"); @@ -35,7 +35,7 @@ struct my_data { ktime_t entry_stamp; }; -/* Here we use the entry_hanlder to timestamp function entry */ +/* Here we use the entry_handler to timestamp function entry */ static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs) { struct my_data *data; @@ -47,6 +47,7 @@ static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs) data->entry_stamp = ktime_get(); return 0; } +NOKPROBE_SYMBOL(entry_handler); /* * Return-probe handler: Log the return value and duration. Duration may turn @@ -66,6 +67,7 @@ static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs) func_name, retval, (long long)delta); return 0; } +NOKPROBE_SYMBOL(ret_handler); static struct kretprobe my_kretprobe = { .handler = ret_handler, @@ -83,7 +85,7 @@ 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); @@ -102,4 +104,5 @@ static void __exit kretprobe_exit(void) module_init(kretprobe_init) module_exit(kretprobe_exit) +MODULE_DESCRIPTION("sample kernel module showing the use of return probes"); MODULE_LICENSE("GPL"); |