Re: stack overflow?

From: Christian Widmer (cwidmer@iiic.ethz.ch)
Date: Wed Sep 26 2001 - 08:46:26 EST


On Wednesday 26 September 2001 15:29, you wrote:
> Christian Widmer wrote:
> > hi
> >
> > i saw very strange behaviour when debuging my modules and i start to
> > think about stack overflow. i know that the kernel stack of eache process
> > is some what smaller than 8KB. but how big is the kernelstack during
> > interrupt time when executing tasklets?
>
> Depends on the architecture, but on the x86 there is no stack switch
> when you receive an interrupt in kernel mode. Thus, if too many
> interrupts occur you could potentially overflow the stack. If
> interrupted from user mode the stack switches to the top of the kernel
> stack.

thanks
i could verify that it was a stackoverflow. but this was due to an
unexpected behaviour of gcc not because of too may interrupts :)
i realiesd that when i had a look at the assemby output of my code.
i had a macro that defined its local variables (256 byte). this macro
was used n times and gcc allocates n * 256 bytes at the function entry
point also it actualy only needs 256 byte. is his allocation strategy
not silly?

chris
        
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