Re: interrupt checks for spinlocks

Pete Zaitcev (zaitcev@redhat.com)
Sun, 3 Nov 2002 19:42:49 -0500


> Date: Sun, 3 Nov 2002 16:28:13 -0800
> From: William Lee Irwin III <wli@holomorphy.com>

> >> (1) check that spinlocks are not taken in interrupt context without
> >> interrupts disabled

> > Bill, why is this bad? I routinely use this technique.
> > -- Pete
>
> If you receive the same interrupt on the same cpu and re-enter code
> that does that, you will deadlock.

How would that happen? I thought it was not possible to re-enter
an interrupt, and that it was pretty fundamental for Linux.
When did we allow it, and what are implications for architectures?

-- Pete
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