[PATCH] macsmc: check for missing SMC to avoid crash

[PATCH] macsmc: check for missing SMC to avoid crash

[Atharva Tiwari]

Users might manually install these drivers
without the core SMC device, causing
a NULL deref. Add a guard and return -ENODEV.

Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
---
 drivers/gpio/gpio-macsmc.c          | 3 +++
 drivers/power/reset/macsmc-reboot.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/gpio/gpio-macsmc.c b/drivers/gpio/gpio-macsmc.c
index 30ef258e7655..7048b45953bb 100644
--- a/drivers/gpio/gpio-macsmc.c
+++ b/drivers/gpio/gpio-macsmc.c
@@ -238,6 +238,9 @@ static int macsmc_gpio_probe(struct platform_device *pdev)
 	smc_key key;
 	int ret;
 
+	if (!smc)
+		return -ENODEV;
+
 	smcgp = devm_kzalloc(&pdev->dev, sizeof(*smcgp), GFP_KERNEL);
 	if (!smcgp)
 		return -ENOMEM;
diff --git a/drivers/power/reset/macsmc-reboot.c b/drivers/power/reset/macsmc-reboot.c
index e9702acdd366..739f94e4ed7e 100644
--- a/drivers/power/reset/macsmc-reboot.c
+++ b/drivers/power/reset/macsmc-reboot.c
@@ -205,6 +205,9 @@ static int macsmc_reboot_probe(struct platform_device *pdev)
 	struct macsmc_reboot *reboot;
 	int ret, i;
 
+	if (!smc)
+		return -ENODEV;
+
 	reboot = devm_kzalloc(&pdev->dev, sizeof(*reboot), GFP_KERNEL);
 	if (!reboot)
 		return -ENOMEM;
-- 
2.43.0

Re: [PATCH] macsmc: check for missing SMC to avoid crash

[Sven Peter]

On 09.10.25 20:37, Atharva Tiwari wrote:
> Users might manually install these drivers
> without the core SMC device, causing

Installing isn't enough; that's not gonna trigger probing any of these 
devices.
Did you run into this issue?

Hitting this should require deliberately creating a broken dts file and 
booting with that one. But if I'm creating a broken dts file I can 
easily crash the kernel in various other ways.



Sven