Re: [uml-devel] system call accessing the host os

[Jeff Dike <jdike@addtoit.com>]

On Wed, Apr 05, 2006 at 10:20:44PM +0200, Olivier Crameri wrote:
> Thanks for the answer. I bumped CONFIG_KERNEL_STACK_ORDER to 3, but it
> doesn't help.

I didn't think so, since the symptoms were wrong.  However, keep that
in the back of your mind since you're dealing with some piggy parts of
libc.

> When I said that using malloc didn't work, I meant the following: I'm
> using malloc to allocate a buffer in the UML kernel. I'm not passing a
> user level buffer to the system call. 

38K isn't big enough for it to fall back to vmalloc, so the pages not
being present probably isn't an issue.

> Then, when I use fread to read
> my file into this buffer, if I read a small number of bytes, it works.
> However when I try to fread the entire file (38k), fread returns 0.

What's the break point between working and non-working?

> Later on, I use sscanf to parse my buffer. No matter what happens,
> sscanf returns 0, which is wrong even if there is no error. The exact
> same code compiled in the host works perfectly.

This, I don't understand.

What version of UML are you using?

				Jeff


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