LinuxLists.cc - [PATCH] [sh/highlander] psw: Add error handling in psw_irq

2023-11-29 06:39:07

Subject: [PATCH] [sh/highlander] psw: Add error handling in psw_irq_handler

This patch adds error handling for the platform_get_drvdata call
within the psw_irq_handler function in
arch/sh/boards/mach-highlander/psw.c. Previously, the absence of
error checking could lead to unexpected behavior if
platform_get_drvdata returned a null pointer.

Signed-off-by: Haoran Liu <[email protected]>
---
arch/sh/boards/mach-highlander/psw.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/sh/boards/mach-highlander/psw.c b/arch/sh/boards/mach-highlander/psw.c
index d445c54f74e4..e079215e50e3 100644
--- a/arch/sh/boards/mach-highlander/psw.c
+++ b/arch/sh/boards/mach-highlander/psw.c
@@ -21,6 +21,12 @@ static irqreturn_t psw_irq_handler(int irq, void *arg)
unsigned int l, mask;
int ret = 0;

+ if (!psw) {
+ pr_err("psw_irq_handler: No push_switch data associated
+ with platform_device\n");
+ return IRQ_NONE;
+ }
+
l = __raw_readw(PA_DBSW);

/* Nothing to do if there's no state change */
--
2.17.1

2023-11-29 08:11:32

by Geert Uytterhoeven

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Subject: Re: [PATCH] [sh/highlander] psw: Add error handling in psw_irq_handler

Hi Haoran,

On Wed, Nov 29, 2023 at 7:38 AM Haoran Liu <[email protected]> wrote:
> This patch adds error handling for the platform_get_drvdata call
> within the psw_irq_handler function in
> arch/sh/boards/mach-highlander/psw.c. Previously, the absence of
> error checking could lead to unexpected behavior if
> platform_get_drvdata returned a null pointer.
>
> Signed-off-by: Haoran Liu <[email protected]>

Thanks for your patch!

> --- a/arch/sh/boards/mach-highlander/psw.c
> +++ b/arch/sh/boards/mach-highlander/psw.c
> @@ -21,6 +21,12 @@ static irqreturn_t psw_irq_handler(int irq, void *arg)
> unsigned int l, mask;
> int ret = 0;
>
> + if (!psw) {
> + pr_err("psw_irq_handler: No push_switch data associated
> + with platform_device\n");
> + return IRQ_NONE;
> + }
> +
> l = __raw_readw(PA_DBSW);
>
> /* Nothing to do if there's no state change */

This means the button is pressed, and the interrupt fired, in
between the calls to request_irq() and platform_set_drvdata() in
arch/sh/drivers/push-switch.c:switch_drv_probe()?

The same issue can happen with arch/sh/boards/mach-landisk/psw.c.
I think the proper solution is to fix this inside the push switch
driver, by moving the call to request_irq() after the call to
platform_set_drvdata() (and doing the reverse in switch_drv_remove()).

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

2023-12-01 09:48:42

by Geert Uytterhoeven

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