The patch titled
gpiolib: fix oops in gpio_get_value_cansleep()
has been removed from the -mm tree. Its filename was
gpiolib-fix-oops-in-gpio_get_value_cansleep.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: gpiolib: fix oops in gpio_get_value_cansleep()
From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
We can get the following oops from gpio_get_value_cansleep() when a GPIO
controller doesn't provide a get() callback:
Unable to handle kernel paging request for instruction fetch
Faulting instruction address: 0x00000000
Oops: Kernel access of bad area, sig: 11 [#1]
[...]
NIP [00000000] 0x0
LR [c0182fb0] gpio_get_value_cansleep+0x40/0x50
Call Trace:
[c7b79e80] [c0183f28] gpio_value_show+0x5c/0x94
[c7b79ea0] [c01a584c] dev_attr_show+0x30/0x7c
[c7b79eb0] [c00d6b48] fill_read_buffer+0x68/0xe0
[c7b79ed0] [c00d6c54] sysfs_read_file+0x94/0xbc
[c7b79ef0] [c008f24c] vfs_read+0xb4/0x16c
[c7b79f10] [c008f580] sys_read+0x4c/0x90
[c7b79f40] [c0013a14] ret_from_syscall+0x0/0x38
It's OK to request the value of *any* GPIO; most GPIOs are bidirectional,
so configuring them as outputs just enables an output driver and doesn't
disable the input logic.
So the problem is that gpio_get_value_cansleep() isn't making the same
sanity check that gpio_get_value() does: making sure this GPIO isn't one
of the atypical "no input logic" cases.
Reported-by: Anton Vorontsov <avorontsov@xxxxxxxxxxxxx>
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.27.x, 2.6.26.x, 2.6.25.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN drivers/gpio/gpiolib.c~gpiolib-fix-oops-in-gpio_get_value_cansleep drivers/gpio/gpiolib.c
--- a/drivers/gpio/gpiolib.c~gpiolib-fix-oops-in-gpio_get_value_cansleep
+++ a/drivers/gpio/gpiolib.c
@@ -1105,7 +1105,7 @@ int gpio_get_value_cansleep(unsigned gpi
might_sleep_if(extra_checks);
chip = gpio_to_chip(gpio);
- return chip->get(chip, gpio - chip->base);
+ return chip->get ? chip->get(chip, gpio - chip->base) : 0;
}
EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
_
Patches currently in -mm which might be from dbrownell@xxxxxxxxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
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