From: Stephen Boyd swboyd@chromium.org
[ Upstream commit 3e779a2e7f909015f21428b66834127496110b6d ]
gpiochip_set_cascaded_irqchip() is passed 'parent_irq' as an argument and then the address of that argument is assigned to the gpio chips gpio_irq_chip 'parents' pointer shortly thereafter. This can't ever work, because we've just assigned some stack address to a pointer that we plan to dereference later in gpiochip_irq_map(). I ran into this issue with the KASAN report below when gpiochip_irq_map() tried to setup the parent irq with a total junk pointer for the 'parents' array.
BUG: KASAN: stack-out-of-bounds in gpiochip_irq_map+0x228/0x248 Read of size 4 at addr ffffffc0dde472e0 by task swapper/0/1
CPU: 7 PID: 1 Comm: swapper/0 Not tainted 4.14.72 #34 Call trace: [<ffffff9008093638>] dump_backtrace+0x0/0x718 [<ffffff9008093da4>] show_stack+0x20/0x2c [<ffffff90096b9224>] __dump_stack+0x20/0x28 [<ffffff90096b91c8>] dump_stack+0x80/0xbc [<ffffff900845a350>] print_address_description+0x70/0x238 [<ffffff900845a8e4>] kasan_report+0x1cc/0x260 [<ffffff900845aa14>] __asan_report_load4_noabort+0x2c/0x38 [<ffffff900897e098>] gpiochip_irq_map+0x228/0x248 [<ffffff900820cc08>] irq_domain_associate+0x114/0x2ec [<ffffff900820d13c>] irq_create_mapping+0x120/0x234 [<ffffff900820da78>] irq_create_fwspec_mapping+0x4c8/0x88c [<ffffff900820e2d8>] irq_create_of_mapping+0x180/0x210 [<ffffff900917114c>] of_irq_get+0x138/0x198 [<ffffff9008dc70ac>] spi_drv_probe+0x94/0x178 [<ffffff9008ca5168>] driver_probe_device+0x51c/0x824 [<ffffff9008ca6538>] __device_attach_driver+0x148/0x20c [<ffffff9008ca14cc>] bus_for_each_drv+0x120/0x188 [<ffffff9008ca570c>] __device_attach+0x19c/0x2dc [<ffffff9008ca586c>] device_initial_probe+0x20/0x2c [<ffffff9008ca18bc>] bus_probe_device+0x80/0x154 [<ffffff9008c9b9b4>] device_add+0x9b8/0xbdc [<ffffff9008dc7640>] spi_add_device+0x1b8/0x380 [<ffffff9008dcbaf0>] spi_register_controller+0x111c/0x1378 [<ffffff9008dd6b10>] spi_geni_probe+0x4dc/0x6f8 [<ffffff9008cab058>] platform_drv_probe+0xdc/0x130 [<ffffff9008ca5168>] driver_probe_device+0x51c/0x824 [<ffffff9008ca59cc>] __driver_attach+0x100/0x194 [<ffffff9008ca0ea8>] bus_for_each_dev+0x104/0x16c [<ffffff9008ca58c0>] driver_attach+0x48/0x54 [<ffffff9008ca1edc>] bus_add_driver+0x274/0x498 [<ffffff9008ca8448>] driver_register+0x1ac/0x230 [<ffffff9008caaf6c>] __platform_driver_register+0xcc/0xdc [<ffffff9009c4b33c>] spi_geni_driver_init+0x1c/0x24 [<ffffff9008084cb8>] do_one_initcall+0x240/0x3dc [<ffffff9009c017d0>] kernel_init_freeable+0x378/0x468 [<ffffff90096e8240>] kernel_init+0x14/0x110 [<ffffff9008086fcc>] ret_from_fork+0x10/0x18
The buggy address belongs to the page: page:ffffffbf037791c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000000() raw: 4000000000000000 0000000000000000 0000000000000000 00000000ffffffff raw: ffffffbf037791e0 ffffffbf037791e0 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffffffc0dde47180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffc0dde47200: f1 f1 f1 f1 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f2 f2
ffffffc0dde47280: f2 f2 00 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3
^ ffffffc0dde47300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffc0dde47380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Let's leave around one unsigned int in the gpio_irq_chip struct for the single parent irq case and repoint the 'parents' array at it. This way code is left mostly intact to setup parents and we waste an extra few bytes per structure of which there should be only a handful in a system.
Cc: Evan Green evgreen@chromium.org Cc: Thierry Reding treding@nvidia.com Cc: Grygorii Strashko grygorii.strashko@ti.com Fixes: e0d897289813 ("gpio: Implement tighter IRQ chip integration") Signed-off-by: Stephen Boyd swboyd@chromium.org Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpio/gpiolib.c | 3 ++- include/linux/gpio/driver.h | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 06dce16e22bb..70f0dedca59f 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1675,7 +1675,8 @@ static void gpiochip_set_cascaded_irqchip(struct gpio_chip *gpiochip, irq_set_chained_handler_and_data(parent_irq, parent_handler, gpiochip);
- gpiochip->irq.parents = &parent_irq; + gpiochip->irq.parent_irq = parent_irq; + gpiochip->irq.parents = &gpiochip->irq.parent_irq; gpiochip->irq.num_parents = 1; }
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 5382b5183b7e..82a953ec5ef0 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -94,6 +94,13 @@ struct gpio_irq_chip { */ unsigned int num_parents;
+ /** + * @parent_irq: + * + * For use by gpiochip_set_cascaded_irqchip() + */ + unsigned int parent_irq; + /** * @parents: *