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Date:   Mon, 25 Oct 2021 15:15:17 +0900
From:   Masami Hiramatsu <mhiramat@kernel.org>
To:     Tiezhu Yang <yangtiezhu@loongson.cn>
Cc:     naveen.n.rao@linux.ibm.com, anil.s.keshavamurthy@intel.com,
        davem@davemloft.net, corbet@lwn.net, ananth@in.ibm.com,
        akpm@linux-foundation.org, randy.dunlap@oracle.com,
        mathieu.desnoyers@polymtl.ca, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] samples/kretprobes: Fix return value if
 register_kretprobe() failed
Message-Id: <20211025151517.f295f7804993e55997f0258f@kernel.org>
In-Reply-To: <1635132660-5038-2-git-send-email-yangtiezhu@loongson.cn>
References: <1635132660-5038-1-git-send-email-yangtiezhu@loongson.cn>
        <1635132660-5038-2-git-send-email-yangtiezhu@loongson.cn>
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On Mon, 25 Oct 2021 11:30:57 +0800
Tiezhu Yang <yangtiezhu@loongson.cn> wrote:

> 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
> 
> Fixes: 804defea1c02 ("Kprobes: move kprobe examples to samples/")
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>

This looks good to me.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thanks!

> ---
>  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 5dc1bf3..228321e 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);
> -- 
> 2.1.0
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>