Re: writing to sysfs appears to hang

[Mike Anderson <andmike@us.ibm.com>]

Paul Larson [plars@linuxtestproject.org] wrote:
> I've been playing with sysfs and notices something odd.  If I do this:
> echo 1 > /sys/devices/sys/name
> the process appears to be hung.  ^c won't return control to me.  If I
> log in on another console though, I can't find it running in the process
> list.  All I can do is kill the login process.  No kernel errors when I
> do this, just the hung terminal.
> 
> -Paul Larson

I repeated your example and in a quick look at the backtrace
the echo is in a loop calling down into sysfs_write_file/dev_attr_store.

I think the problem is that if a device does not have a attribute store
function the return value from dev_attr_store is incorrect.

-andmike
--
Michael Anderson
andmike@us.ibm.com