Re: [PATCH 1/1] kprobes: Deletion of an unnecessary check before the function call "module_put"

Masami Hiramatsu
2014-11-17T08:23:53Z

(2014/11/16 21:34), SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 16 Nov 2014 12:20:31 +0100
>
> The module_put() function tests whether its argument is NULL and then
> returns immediately. Thus the test around the call is not needed.
>
> This issue was detected by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> kernel/kprobes.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 3995f54..f1e7d45 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1527,8 +1527,7 @@ int register_kprobe(struct kprobe *p)
> out:
> mutex_unlock(&kprobe_mutex);
>
> - if (probed_mod)
> - module_put(probed_mod);
> + module_put(probed_mod);

This is OK, but I you request a comment line over there so that
code reader can understand it is safe to pass a NULL pointer to
module_put().

# and of course don't touch jump label around that :)

Thank you,

>
> return ret;
> }
>

--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com