[PATCH v2] gpio: nuvoton: Fix sgpio irq handle error

[PATCH v2] gpio: nuvoton: Fix sgpio irq handle error

[Jim Liu]

User use gpiomon to monitor input pin ,if triger the system will call trace and rcu stall.

The irq_handler uses generic_handle_domain_irq, so there is need to remove irq_find_mapping.

Fixes: c4f8457d17ce ("gpio: nuvoton: Add Nuvoton NPCM sgpio driver")
Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
---
Changes for v2:
   - add more description
---
 drivers/gpio/gpio-npcm-sgpio.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/gpio/gpio-npcm-sgpio.c b/drivers/gpio/gpio-npcm-sgpio.c
index d31788b43abc..136838c25756 100644
--- a/drivers/gpio/gpio-npcm-sgpio.c
+++ b/drivers/gpio/gpio-npcm-sgpio.c
@@ -443,11 +443,9 @@ static void npcm_sgpio_irq_handler(struct irq_desc *desc)
 		const struct npcm_sgpio_bank *bank = &npcm_sgpio_banks[i];
 
 		reg = ioread8(bank_reg(gpio, bank, EVENT_STS));
-		for_each_set_bit(j, &reg, 8) {
-			girq = irq_find_mapping(gc->irq.domain,
-						i * 8 + gpio->nout_sgpio + j);
-			generic_handle_domain_irq(gc->irq.domain, girq);
-		}
+		for_each_set_bit(j, &reg, 8)
+			generic_handle_domain_irq(gc->irq.domain,
+						  i * 8 + gpio->nout_sgpio + j);
 	}
 
 	chained_irq_exit(ic, desc);
-- 
2.25.1

Re: [PATCH v2] gpio: nuvoton: Fix sgpio irq handle error

[Dan Carpenter]

On Mon, Apr 29, 2024 at 02:06:42PM +0800, Jim Liu wrote:
> User use gpiomon to monitor input pin ,if triger the system will call trace and rcu stall.
> 
> The irq_handler uses generic_handle_domain_irq, so there is need to remove irq_find_mapping.
> 
> Fixes: c4f8457d17ce ("gpio: nuvoton: Add Nuvoton NPCM sgpio driver")
> Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
> ---
> Changes for v2:
>    - add more description

Part of the commit is missing so it will break the build.

drivers/gpio/gpio-npcm-sgpio.c: In function ‘npcm_sgpio_irq_handler’:
drivers/gpio/gpio-npcm-sgpio.c:437:28: warning: unused variable ‘girq’ [-Wunused-variable]
  437 |         unsigned int i, j, girq;
      |                            ^~~~

Thanks for improving the commit message and adding a Fixes tag.  That's
very helpful, but it still can be improved a bit.

======================================

Subject: [PATCH v3] gpio: nuvoton: Fix stall in npcm_sgpio_irq_handler()

The generic_handle_domain_irq() function calls irq_resolve_mapping()
so calling irq_find_mapping() is duplicative and will lead to a stack
trace and an RCU stall.

[ cut and paste the call trace here]

Fixes: c4f8457d17ce ("gpio: nuvoton: Add Nuvoton NPCM sgpio driver")
Signed-off-by:

======================================

Otherwise it looks good.  Please fix and resend.

regards,
dan carpenter