Re: [patch] entry.S calling schedule() with interrupts disabled, 2.2.2

Linus Torvalds (torvalds@transmeta.com)
Mon, 1 Mar 1999 10:41:05 -0800 (PST)

On Mon, 1 Mar 1999, Ingo Molnar wrote:
>
> maybe i'm misunderstanding something, but i'm trying to catch exactly such
> code, because i think it's buggy. schedule() does not guarantee that the
> 'interrupt state' (IF on UP, the more complex interrupt state on SMP) is
> preserved.

Indeed. In fact it guarantees that it is dropped, whatever the state was
before.

A lot of tests are volatile in only one direction - you're waiting for a
buffer to not be empty any more, and the filling is asynchronous, but the
emptying is not.

Linus

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