Re: [PATCH] gpio: Request interrupts after IRQ is initialized

From: Shreeya Patel
Date: Thu Apr 14 2022 - 15:11:51 EST



On 14/04/22 08:27, Mario Limonciello wrote:
commit 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members before
initialization") attempted to fix a race condition that lead to a NULL
pointer, but in the process caused a regression for _AEI/_EVT declared
GPIOs. This manifests in messages showing deferred probing while trying
to allocate IRQs like so:

[ 0.688318] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0000 to IRQ, err -517
[ 0.688337] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x002C to IRQ, err -517
[ 0.688348] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003D to IRQ, err -517
[ 0.688359] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003E to IRQ, err -517
[ 0.688369] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003A to IRQ, err -517
[ 0.688379] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003B to IRQ, err -517
[ 0.688389] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0002 to IRQ, err -517
[ 0.688399] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0011 to IRQ, err -517
[ 0.688410] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0012 to IRQ, err -517
[ 0.688420] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0007 to IRQ, err -517

The code for walking _AEI doesn't handle deferred probing and so this leads
to non-functional GPIO interrupts.

Fix this issue by moving the call to `acpi_gpiochip_request_interrupts` to
occur after gc->irc.initialized is set.


Thanks Mario for sending a fix for this issue, I didn't realize gpiod_to_irq() was also
being called through acpi_gpiochip_request_interrupts().
Change looks good to me.
Reviewed-by: Shreeya Patel <shreeya.patel@xxxxxxxxxxxxx>

Cc: Shreeya Patel <shreeya.patel@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members before initialization")
Reported-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Link: https://lore.kernel.org/linux-gpio/BL1PR12MB51577A77F000A008AA694675E2EF9@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/T/#u
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
drivers/gpio/gpiolib.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 085348e08986..b7694171655c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1601,8 +1601,6 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
gpiochip_set_irq_hooks(gc);
- acpi_gpiochip_request_interrupts(gc);
-
/*
* Using barrier() here to prevent compiler from reordering
* gc->irq.initialized before initialization of above
@@ -1612,6 +1610,8 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
gc->irq.initialized = true;
+ acpi_gpiochip_request_interrupts(gc);
+
return 0;
}