Re: kernel stack size

From: Al Viro
Date: Sat Apr 02 2005 - 14:38:59 EST


On Sat, Apr 02, 2005 at 02:04:11PM -0500, Steven Rostedt wrote:
> You can also use globally static variables too. But this makes for
> non-reentry code.
>
> Sometimes I don't feel that a kmalloc is worth it, and if the function
> in question for the driver would seldom have problems with reentry, I
> use a statically defined global, and protect it with spin_locks. If
> these can also be used in interrupt context, you need to use the
> spin_lock_irqsave variants. But don't do this if the critical section
> has long latencies.

... and the first time copy_from_user() blocks under your spinlock
you will get a nice shiny deadlock.
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