Commit c0017ed71966 ("gpio: Introduce gpio descriptor 'name'") causes
OOPS on boot on LPC32xx boards:
Unable to handle kernel NULL pointer dereference at virtual address 00000000
CPU: 0 PID: 1 Comm: swapper Not tainted 4.3.0+ #707
Hardware name: LPC32XX SoC (Flattened Device Tree)
task: c381baa0 ti: c381e000 task.ti: c381e000
PC is at strcmp+0x10/0x40
LR is at gpiochip_add+0x3d0/0x4d4
pc : [<>] lr : [<>] psr: a0000093
sp : c381fd60 ip : c381fd70 fp : c381fd6c
[snip]
Backtrace:
[<>] (strcmp) from [<>] (gpiochip_add+0x3d0/0x4d4)
[<>] (gpiochip_add) from [<>] (lpc32xx_gpio_probe+0x44/0x60)
[<>] (lpc32xx_gpio_probe) from [<>] (platform_drv_probe+0x40/0x8c)
[<>] (platform_drv_probe) from [<>] (driver_probe_device+0x110/0x294)
[<>] (driver_probe_device) from [<>] (__driver_attach+0x70/0x94)
[<>] (__driver_attach) from [<>] (bus_for_each_dev+0x74/0x98)
[<>] (bus_for_each_dev) from [<>] (driver_attach+0x20/0x28)
[<>] (driver_attach) from [<>] (bus_add_driver+0xd4/0x1f0)
[<>] (bus_add_driver) from [<>] (driver_register+0xa4/0xe8)
[<>] (driver_register) from [<>] (__platform_driver_register+0x38/0x4c)
[<>] (__platform_driver_register) from [<>]
(lpc32xx_gpio_driver_init+0x18/0x20)
[<>] (lpc32xx_gpio_driver_init) from [<>] (do_one_initcall+0x108/0x1c8)
[<>] (do_one_initcall) from [<>] (kernel_init_freeable+0x10c/0x1d4)
[<>] (kernel_init_freeable) from [<>] (kernel_init+0x10/0xec)
[<>] (kernel_init) from [<>] (ret_from_fork+0x14/0x24)
This is caused by the fact that at the moment some GPIO names are set
to NULL, there is a hole in linear representation of one GPI bank, see
drivers/gpio/gpio-lpc32xx.c / gpi_p3_names[] for details.
The same problem most probably affects also gpio-cs5535.c, see
cs5535_gpio_names[].
Signed-off-by: Vladimir Zapolskiy <[email protected]>
---
Linus, Markus,
I understand that LPC32xx GPIO driver is ugly (hopefully this
will be changed in future), but please account this problem.
I don't ask for inclusion of this change, because my own analysis is
not done completely.
Also please review, the same problem probably affects gpio-cs5535.c
as well, see cs5535_gpio_names[].
drivers/gpio/gpiolib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a18f00f..2a91f32 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -233,7 +233,7 @@ static struct gpio_desc *gpio_name_to_desc(const char *
const name)
for (i = 0; i != chip->ngpio; ++i) {
struct gpio_desc *gpio = &chip->desc[i];
- if (!gpio->name)
+ if (!gpio->name || !name)
continue;
if (!strcmp(gpio->name, name)) {
--
2.5.0
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