From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 13 May 2015 20:49:12 +0000 (+0200)
Subject: rtmutex: Warn if trylock is called from hard/softirq context
X-Git-Tag: omap-for-v4.3/legacy-v2-signed~211^2~5
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6ce47fd961fa8fb206433789d7754c73cab3b5d0;p=pandora-kernel.git

rtmutex: Warn if trylock is called from hard/softirq context

rt_mutex_trylock() must be called from thread context. It can be
called from atomic regions (preemption or interrupts disabled), but
not from hard/softirq/nmi context. Add a warning to alert abusers.

The reasons for this are:

    1) There is a potential deadlock in the slowpath

    2) Another cpu which blocks on the rtmutex will boost the task
       which allegedly locked the rtmutex, but that cannot work
       because the hard/softirq context borrows the task context.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
---

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