Subject: [PATCH] at91: pmc: Fixed irq's name allocation for programmable clocks

From: [email-masked] (boris brezillon)
Date: Mon, 03 Feb 2014 18:13:21 +0100

Hello JJ,

On 03/02/2014 17:46, Jean-Jacques Hiblot wrote:
> The name provided to request_irq() must be valid until the irq is
> released.
> This patch allocates and formats the string with kasprintf().

Thanks for reporting this bug.

>
> Signed-off-by: Jean-Jacques Hiblot <[email-masked]>
> ---
>   drivers/clk/at91/clk-programmable.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
> index 8e242c7..0f8bf0f 100644
> --- a/drivers/clk/at91/clk-programmable.c
> +++ b/drivers/clk/at91/clk-programmable.c
> @@ -19,6 +19,7 @@
>   #include <linux/sched.h>
>   #include <linux/interrupt.h>
>   #include <linux/irq.h>
> +#include <linux/string.h>
>   
>   #include "pmc.h"
>   
> @@ -247,7 +248,7 @@ at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,
>   	struct clk_programmable *prog;
>   	struct clk *clk = NULL;
>   	struct clk_init_data init;
> -	char irq_name[11];
> +	char *irq_name;
>   
>   	if (id > PROG_ID_MAX)
>   		return ERR_PTR(-EINVAL);
> @@ -269,7 +270,7 @@ at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,
>   	prog->irq = irq;
>   	init_waitqueue_head(&prog->wait);
>   	irq_set_status_flags(prog->irq, IRQ_NOAUTOEN);
> -	snprintf(irq_name, sizeof(irq_name), "clk-prog%d", id);
> +	irq_name = kasprintf(GFP_KERNEL, "clk-prog%d", id);

Could you either use a static table with the prog clk names or store the 
name in
the clk_programmable struct ?
This way we could avoid the additional dynamic allocation.

static prog_clk_names = {
   "clk-prog0",
[...]
   "clk-prog7",
};

[...]
     ret = request_irq(prog->irq, clk_programmable_irq_handler, 
IRQF_TRIGGER_HIGH, prog_clk_names[id], prog);

or

struct clk_programmable {
[...]
     char irq_name[11];
[...]
};

[...]

snprintf(prog->irq_name, sizeof(prog->irq_name), "clk-prog%d", id);
ret = request_irq(prog->irq, clk_programmable_irq_handler, 
IRQF_TRIGGER_HIGH, prog->irq_name, prog);

Best Regards,

Boris
>   	ret = request_irq(prog->irq, clk_programmable_irq_handler,
>   			  IRQF_TRIGGER_HIGH, irq_name, prog);
>   	if (ret)