Re: [PATCH] fs/devfs/base.c

[Richard Gooch <rgooch@ras.ucalgary.ca>]

Linus Torvalds writes:
> 
> On Sun, 27 May 2001, Richard Gooch wrote:
> > 
> > I absolutely don't want this patch applied. It's bogus. It is entirely
> > safe to alloc 1 kB on the stack in this code, since it has a short and
> > well-controlled code path from syscall entry to the function.
> 
> IT IS NEVER EVER SAFE TO ALLOCATE 1kB OF STACK!

I can see you care about this ;-)

> Why?
>  - the kernel stack is 4kB, and _nobody_ has the right to eat up a
>    noticeable portion of it. It doesn't matter if you "know" your caller
>    or not: you do not know what interrupts happen during this time, and
>    how much stack they want.

OK, that's a good point. Easy solution: disable interrupts in that
function.

Only kidding.

> Ergo: the simple rule of "don't allocate big structures of the
> stack" is always a good rule, and making excuses for it is bad.

OK, well, I can make the structure static instead, since the function
is single-threaded anyway.

				Regards,

					Richard....
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