Re: [PATCH] 2.6.19-rc2-mm2 sysfs: sysfs_write_file() writes zero terminated data

From: Greg KH
Date: Mon Oct 23 2006 - 17:18:52 EST


On Mon, Oct 23, 2006 at 10:02:03PM +0200, Thomas Maier wrote:
> Hello,
>
> Sorry, maybe i missed something, but according to the
> code in fs/sysfs/file.c the "write" sequence is:
>
> - call to sysfs_write_file(ubuf, count)
> - if (!sysfsbuf->page) alloc zeroed page
> - copy count bytes from ubuf to sysfsbuf->page
> - call store(sysfsbuf->page, count)
>
> When you write again to the file before closing it
> (possible?!), and count is less the the previous count
> you may not pass a zero terminated string/data to store().

Yeah, that might happen, but writing to a sysfs file again after the
first time is not the normal case here. I'll add your patch to the
queue to keep this from happening though, good catch.

greg k-h
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