Re: [patch V4 part 1 18/36] samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers.

Alexandre Chartre
2020-05-06T16:00:04Z

On 5/5/20 3:16 PM, Thomas Gleixner wrote:
> From: Masami Hiramatsu <mhiramat@kernel.org>
>
> Add __kprobes and NOKPROBE_SYMBOL() for sample kprobe handlers.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Link: https://lkml.kernel.org/r/158523421177.24735.16273975317343670204.stgit@devnote2
>
> ---
> samples/kprobes/kprobe_example.c | 6 ++++--
> samples/kprobes/kretprobe_example.c | 2 ++
> 2 files changed, 6 insertions(+), 2 deletions(-)

Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>

alex.

>
> --- a/samples/kprobes/kprobe_example.c
> +++ b/samples/kprobes/kprobe_example.c
> @@ -25,7 +25,7 @@ static struct kprobe kp = {
> };
>
> /* kprobe pre_handler: called just before the probed instruction is executed */
> -static int handler_pre(struct kprobe *p, struct pt_regs *regs)
> +static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
> {
> #ifdef CONFIG_X86
> pr_info("<%s> pre_handler: p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
> @@ -54,7 +54,7 @@ static int handler_pre(struct kprobe *p,
> }
>
> /* kprobe post_handler: called after the probed instruction is executed */
> -static void handler_post(struct kprobe *p, struct pt_regs *regs,
> +static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
> unsigned long flags)
> {
> #ifdef CONFIG_X86
> @@ -90,6 +90,8 @@ static int handler_fault(struct kprobe *
> /* Return 0 because we don't handle the fault. */
> return 0;
> }
> +/* NOKPROBE_SYMBOL() is also available */
> +NOKPROBE_SYMBOL(handler_fault);
>
> static int __init kprobe_init(void)
> {
> --- a/samples/kprobes/kretprobe_example.c
> +++ b/samples/kprobes/kretprobe_example.c
> @@ -48,6 +48,7 @@ static int entry_handler(struct kretprob
> data->entry_stamp = ktime_get();
> return 0;
> }
> +NOKPROBE_SYMBOL(entry_handler);
>
> /*
> * Return-probe handler: Log the return value and duration. Duration may turn
> @@ -67,6 +68,7 @@ static int ret_handler(struct kretprobe_
> func_name, retval, (long long)delta);
> return 0;
> }
> +NOKPROBE_SYMBOL(ret_handler);
>
> static struct kretprobe my_kretprobe = {
> .handler = ret_handler,
>