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authorStephen Boyd <swboyd@chromium.org>2018-10-08 09:32:13 -0700
committerLinus Walleij <linus.walleij@linaro.org>2018-10-10 14:03:27 +0200
commit3e779a2e7f909015f21428b66834127496110b6d (patch)
treee6cc2a6e4e82f1e0ddf47e8029fbe6ad9985902a
parent0238df646e6224016a45505d2c111a24669ebe21 (diff)
gpio: Assign gpio_irq_chip::parents to non-stack pointergpio-v4.19-4
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>
-rw-r--r--drivers/gpio/gpiolib.c3
-rw-r--r--include/linux/gpio/driver.h7
2 files changed, 9 insertions, 1 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a57300c1d649..25187403e3ac 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1682,7 +1682,8 @@ 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 0ea328e71ec9..a4d5eb37744a 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -95,6 +95,13 @@ struct gpio_irq_chip {
unsigned int num_parents;
/**
+ * @parent_irq:
+ *
+ * For use by gpiochip_set_cascaded_irqchip()
+ */
+ unsigned int parent_irq;
+
+ /**
* @parents:
*
* A list of interrupt parents of a GPIO chip. This is owned by the

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