Hello folks,
I'm writing a simple device driver and want to expose some of its
attributes to userspace via sysfs.
As usually, I have main device description structure "struct
mydev_info". I've embedded a struct device object there. What I do is:
struct mydev_info mydev
{
struct device *dev;
... bla bla bla ...
} mydev;
mydev->dev=kzalloc(sizeof(struct device), GFP_KERNEL);
mydev->dev->bus_id = "mydev";
mydev->dev->release = mydev_release;
err = device_register(&mydev->dev);
Then, I see /sys/devices/mydev/ in sysfs. I open
pre-defined /sys/devices/mydev/power/state in userspace and don't close it.
Then I run lsmod, and see zero refcount to my module. Well, I run rmmod
mymod, module is unloaded.
Then I close /sys/devices/mydev/power/state, and enjoy segfault.
I thought sysfs subsystem have to increase module refcount when one
opens its sysfs files. Well, there is a release function, but it is also
unloaded with the module.
May be there is a problem because of I have mydev->dev->parent == NULL,
mydev->dev->bus == NULL, mydev->dev->driver == NULL? But I really don't
have any bus, any parent and I don't want to introduce struct
device_driver ...
Kernel is 2.6.15.1.
Although this is my first meet with sysfs, this looks strange.
Thanks.
--
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.
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