Messages in this thread Patch in this message | | | Date | Tue, 19 Nov 2002 18:02:05 +0100 | From | Jens Axboe <> | Subject | Re: writing to sysfs appears to hang |
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On Fri, Nov 15 2002, Mike Anderson wrote: > 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.
This has been in the deadline-rbtree patches for some time (uses writes to sysfs, too).
===== fs/sysfs/inode.c 1.59 vs edited ===== --- 1.59/fs/sysfs/inode.c Wed Oct 30 21:27:35 2002 +++ edited/fs/sysfs/inode.c Fri Nov 8 14:33:59 2002 @@ -243,7 +243,7 @@ if (kobj && kobj->subsys) ops = kobj->subsys->sysfs_ops; if (!ops || !ops->store) - return 0; + return -EINVAL; page = (char *)__get_free_page(GFP_KERNEL); if (!page)
-- Jens Axboe
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