Commit 1d66c64c authored Apr 18, 2005 by Jean Delvare Committed by Greg KH Apr 18, 2005

[PATCH] I2C: Fix incorrect sysfs file permissions in it87 and via686a drivers

The it87 and via686a hardware monitoring drivers each create a sysfs
file named "alarms" in R/W mode, while they should really create it in
read-only mode. Since we don't provide a store function for these files,
write attempts to these files will do something undefined (I guess) and
bad (I am sure). My own try resulted in a locked terminal (where I
attempted the write) and a 100% CPU load until next reboot.

As a side note, wouldn't it make sense to check, when creating sysfs
files, that readable files have a non-NULL show method, and writable
files have a non-NULL store method? I know drivers are not supposed to
do stupid things, but there is already a BUG_ON for several conditions
in sysfs_create_file, so maybe we could add two more?

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent 86b5ac87

drivers/i2c/chips/it87.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -668,7 +668,7 @@ static ssize_t show_alarms(struct device dev, char buf)
		struct it87_data *data = it87_update_device(dev);
		return sprintf(buf,"%d\n", ALARMS_FROM_REG(data->alarms));
		}
		static DEVICE_ATTR(alarms, S_IRUGO \| S_IWUSR, show_alarms, NULL);
		static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

		static ssize_t
		show_vrm_reg(struct device dev, char buf)

drivers/i2c/chips/via686a.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -574,7 +574,7 @@ static ssize_t show_alarms(struct device dev, char buf) {
		struct via686a_data *data = via686a_update_device(dev);
		return sprintf(buf,"%d\n", ALARMS_FROM_REG(data->alarms));
		}
		static DEVICE_ATTR(alarms, S_IRUGO \| S_IWUSR, show_alarms, NULL);
		static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

		/* The driver. I choose to use type i2c_driver, as at is identical to both
		smbus_driver and isa_driver, and clients could be of either kind */

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