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Date:      Mon, 23 Jul 2001 17:46:43 +0400 (MSD)
From:      "Eugene L. Vorokov" <vel@bugz.infotecs.ru>
To:        Mike Smith <msmith@freebsd.org>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: using syscalls in a module (stack problem ?)
Message-ID:  <200107231346.f6NDkh403679@bugz.infotecs.ru>
In-Reply-To: <200107222028.f6MKSgI01274@mass.dis.org> "from Mike Smith at Jul 22, 2001 01:28:42 pm"

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> > I call this function with (curproc, PATH_MAX+1), and everything is fine
> > when I have just a few local variables defined in the caller (it all
> > works on MOD_LOAD only). However, if I have 2 buffers, 4096 bytes each,
> > as local variables and then try to allocate userspace memory the same
> > way, kernel crashes - sometimes inside mmap(), sometimes a bit later.
> > 
> > Why could this happen ? Is it related to possible stack overflow ?
> 
> Yes.  The kernel stack is only two pages; you absolutely must not use 
> large local variables in the kernel.

I see. But I still can define them using "static", right ?

Regards,
Eugene


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