Re: [PATCH] proc_file_read() (Was: Re: proc_file_read() question)

From: Mike Galbraith (
Date: Tue Jun 26 2001 - 15:35:45 EST

On Tue, 26 Jun 2001, Martin Wilck wrote:

> Hi,
> > Shhh ;-) Last time that hack was mentioned, someone wanted to _remove_
> > it. It's a very nice little hack to have around, and IKD uses it.
> I am not saying it should be removed. But IMO it is a legitimate (if
> not the originally intended) use of "start" to serve as a pointer to
> a memory area allocated in the proc_read () function. This use is broken
> with this hack in its current form, because reading from such a file
> will fail depending on the (random) order of the page and start pointers.
> If I understand the "hack" right, legitimate offsets generated for it
> are always between 0 and PAGE_SIZE. Therefore the patch below would
> not break it, while overcoming the abovementioned problem, because
> legitimate page pointers will never be < PAGE_SIZE.

It's dead simple. My variable length data often didn't quite fit into
the transport vehicle.. so I whacked the excess to avoid the fault.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

This archive was generated by hypermail 2b29 : Sat Jun 30 2001 - 21:00:15 EST