Date: Thu, 3 Dec 2015 10:33:50 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Tejun Heo <tj@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>, Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 1/2] watchdog: introduce touch_softlockup_watchdog_sched()
Message-ID: <20151203093350.GP17308@twins.programming.kicks-ass.net>
References: <20151203002810.GJ19878@mtj.duckdns.org>
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On Wed, Dec 02, 2015 at 07:28:10PM -0500, Tejun Heo wrote:
> Hello,
> 
> There haven't been too many workqueue stall bugs; however, good part
> of them have been pretty painful to track down because there's no
> lockup detection mechanism for workqueue and it isn't easy to tell
> what's going on with workqueues; furthermore, some requirements are
> tricky to get right - e.g. it's not too difficult to miss
> WQ_MEM_RECLAIM for a workqueue which runs a work item which is flushed
> by something which sits in the reclaim path.

have you considered something as simple as:

	WARN_ON(current->reclaim_state && !WQ_MEM_RECLAIM);

?
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