Re: Kernel semaphores

[Pete Zaitcev]

On Tue, 14 Sep 2004 15:25:24 +1000
James Roper <u3205097@xxxxxxxxxx> wrote:

> [] So my question is, if my semaphore is 
> causing that error, what possible things could be triggering it?  Could it be 
> an interrupt while waiting to acquire the semaphore?  I'm using the 
> down_interruptible() to acquire and up() to release.

You have to use spinlocks to provide a mutual exclusion to interrupts.
However, a process on CPU cannot sleep while holding a spinlock. So,
sometimes it's needed to create a derivative locking scheme, based
on spinlocks. A common trick is to combine semaphores and spinlocks.
I cannot be more specific without knowing your code.

-- Pete
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