Re: [Fwd: problem involving wait_on_bh]

Alan Cox (alan@lxorguk.ukuu.org.uk)
Sun, 19 Dec 1999 14:27:47 +0000 (GMT)

> > disable_irq() while holding a lock used in the irq handler
>
> My experience with locks and SMP is that you hang the machine if you
> forget to unlock a lock (e.g. because of an error exit) and an
> interrupt (trying to aquire the lock) happens.

The disable_irq one is very distinctive and an easy trap to fall into

you end up doing

irq_begins
grab_lock_irqsave()
grab_lock()
[spins]
disable_irq()
[spins waiting for irq exit]

Alan

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