[PATCH] ptp: drop redundant kasprintf() to create worker name

[PATCH] ptp: drop redundant kasprintf() to create worker name

[Rasmus Villemoes]

Building with -Wformat-nonliteral, gcc complains

drivers/ptp/ptp_clock.c: In function ‘ptp_clock_register’:
drivers/ptp/ptp_clock.c:239:26: warning: format not a string literal and no format arguments [-Wformat-nonliteral]
            worker_name : info->name);

kthread_create_worker takes fmt+varargs to set the name of the
worker, and that happens with a vsnprintf() to a stack buffer (that is
then copied into task_comm). So there's no reason not to just pass
"ptp%d", ptp->index to kthread_create_worker() and avoid the
intermediate worker_name variable.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/ptp/ptp_clock.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 7eacc1c4b3b1..5419a89d300e 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -232,12 +232,8 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	init_waitqueue_head(&ptp->tsev_wq);
 
 	if (ptp->info->do_aux_work) {
-		char *worker_name = kasprintf(GFP_KERNEL, "ptp%d", ptp->index);
-
 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
-		ptp->kworker = kthread_create_worker(0, worker_name ?
-						     worker_name : info->name);
-		kfree(worker_name);
+		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
 		if (IS_ERR(ptp->kworker)) {
 			err = PTR_ERR(ptp->kworker);
 			pr_err("failed to create ptp aux_worker %d\n", err);
-- 
2.19.1.6.gbde171bbf5

Re: [PATCH] ptp: drop redundant kasprintf() to create worker name

[Richard Cochran]

On Fri, Oct 26, 2018 at 11:22:59PM +0200, Rasmus Villemoes wrote:
> Building with -Wformat-nonliteral, gcc complains
> 
> drivers/ptp/ptp_clock.c: In function ‘ptp_clock_register’:
> drivers/ptp/ptp_clock.c:239:26: warning: format not a string literal and no format arguments [-Wformat-nonliteral]
>             worker_name : info->name);
> 
> kthread_create_worker takes fmt+varargs to set the name of the
> worker, and that happens with a vsnprintf() to a stack buffer (that is
> then copied into task_comm). So there's no reason not to just pass
> "ptp%d", ptp->index to kthread_create_worker() and avoid the
> intermediate worker_name variable.

Acked-by: Richard Cochran <richardcochran@gmail.com>

Re: [PATCH] ptp: drop redundant kasprintf() to create worker name

[Kees Cook]

On Fri, Oct 26, 2018 at 10:22 PM, Rasmus Villemoes
<linux@rasmusvillemoes.dk> wrote:
> Building with -Wformat-nonliteral, gcc complains
>
> drivers/ptp/ptp_clock.c: In function ‘ptp_clock_register’:
> drivers/ptp/ptp_clock.c:239:26: warning: format not a string literal and no format arguments [-Wformat-nonliteral]
>             worker_name : info->name);
>
> kthread_create_worker takes fmt+varargs to set the name of the
> worker, and that happens with a vsnprintf() to a stack buffer (that is
> then copied into task_comm). So there's no reason not to just pass
> "ptp%d", ptp->index to kthread_create_worker() and avoid the
> intermediate worker_name variable.
>
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  drivers/ptp/ptp_clock.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
> index 7eacc1c4b3b1..5419a89d300e 100644
> --- a/drivers/ptp/ptp_clock.c
> +++ b/drivers/ptp/ptp_clock.c
> @@ -232,12 +232,8 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
>         init_waitqueue_head(&ptp->tsev_wq);
>
>         if (ptp->info->do_aux_work) {
> -               char *worker_name = kasprintf(GFP_KERNEL, "ptp%d", ptp->index);
> -
>                 kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
> -               ptp->kworker = kthread_create_worker(0, worker_name ?
> -                                                    worker_name : info->name);
> -               kfree(worker_name);
> +               ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
>                 if (IS_ERR(ptp->kworker)) {
>                         err = PTR_ERR(ptp->kworker);
>                         pr_err("failed to create ptp aux_worker %d\n", err);
> --
> 2.19.1.6.gbde171bbf5
>



-- 
Kees Cook

Re: [PATCH] ptp: drop redundant kasprintf() to create worker name

[David Miller]

From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Fri, 26 Oct 2018 23:22:59 +0200

> Building with -Wformat-nonliteral, gcc complains
> 
> drivers/ptp/ptp_clock.c: In function ‘ptp_clock_register’:
> drivers/ptp/ptp_clock.c:239:26: warning: format not a string literal and no format arguments [-Wformat-nonliteral]
>             worker_name : info->name);
> 
> kthread_create_worker takes fmt+varargs to set the name of the
> worker, and that happens with a vsnprintf() to a stack buffer (that is
> then copied into task_comm). So there's no reason not to just pass
> "ptp%d", ptp->index to kthread_create_worker() and avoid the
> intermediate worker_name variable.
> 
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>

Applied.