Re: [PATCH] Documentation: kernel-locking: mutex_trylock cannot be used in interrupt context

From: Rusty Russell
Date: Wed Aug 18 2010 - 20:52:53 EST


On Thu, 19 Aug 2010 07:38:15 am Stefan Richter wrote:
> Chapter 6 is right about mutex_trylock, but chapter 10 wasn't.
> This error was introduced during semaphore-to-mutex conversion of the
> Unreliable guide. :-)
>
> If user context which performs mutex_lock() or mutex_trylock() is
> preempted by interrupt context which performs mutex_trylock() on the
> same mutex instance, a deadlock occurs. This is because these functions
> do not disable local IRQs when they operate on mutex->wait_lock.

Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

I'm assuming Andrew Morton or Randy Dunlap will pick this up...

Thanks!
Rusty.
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