From d06165b329c04c8050c4b744c05ec61046709490 Mon Sep 17 00:00:00 2001 From: Vladimir Zapolskiy Date: Wed, 11 Nov 2015 14:36:53 +0200 Subject: [PATCH] gpiolib: fix oops, if gpio name is NULL 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 Signed-off-by: Linus Walleij --- 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 a18f00fc1bb8..2a91f3287e3b 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)) { -- 2.20.1