Re: [regression] Latest git has WARN_ON storm with e1000e driver

From: Christian Borntraeger
Date: Fri Oct 03 2008 - 11:21:38 EST


Am Freitag, 3. Oktober 2008 schrieben Sie:
> Which spinlock is it? It sure shouldn't be anything in the generic drievr
> layer: __driver_attach takes a lock, but it's a semaphore (dev->sem), not
> a spinlock. In fact, al lot of drivers will sleep or do allocations, so if
> the driver layer were to call the probe function with a spinlock held,
> things would be really broken.
>
> The callchain has "spin_lock_irqsave" in it, but that's stale stack data.

Very good point indeed. Seems my analysis was wrong. I made a short test and
preempt_count() returns 1 when the WARN_ON triggers. So its either a spinlock
or something else that increased my preempt_count.
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