From: Tejun Heo <tj@kernel.org>
To: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Alex Dubov <oakad@yahoo.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 memstick: support for legacy sony memsticks
Date: Tue, 25 Sep 2012 12:40:17 -0700 [thread overview]
Message-ID: <20120925194017.GK16296@google.com> (raw)
In-Reply-To: <1348601679.12068.17.camel@maxim-laptop>
On Tue, Sep 25, 2012 at 09:34:39PM +0200, Maxim Levitsky wrote:
> But this just adds the WQ_UNBOUND. Dunno, without lock I had several
> crashes, that for high level of confidence caused by by parallel
> execution of work items. Once I added this mutex, I couldnt reproduce
> these.
Yes the combination of WQ_UNBOUND and max_active==1 guarantees
strictly ordered one-by-one execution.
> I had the __blk_end_request fail with NULL msb->req. I can't see how
> that can happen if work queue isn't executed in parallel.
> (and then the I didn't even had by mistake the code that sets it to NULL
> in msb_stop, so I really fail to see how that could happen due internal
> bug in my code.
If you're seeing parallel execution w/ ordered workqueue, it is a
critical bug which would make the kernel crash left and right. Please
try alloc_ordered_workqueue() and if you still see parallel execution,
please report.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-09-25 19:40 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-25 8:38 [PATCH v2 memstick: support for legacy sony memsticks Maxim Levitsky
2012-09-25 8:38 ` [PATCH 1/2] scatterlist: add sg_nents Maxim Levitsky
2012-09-25 8:38 ` [PATCH 2/2] memstick: add support for legacy memorysticks Maxim Levitsky
2012-09-25 18:25 ` Tejun Heo
2012-09-25 19:26 ` Maxim Levitsky
2012-09-25 19:38 ` Tejun Heo
2012-09-25 20:24 ` Maxim Levitsky
2012-09-25 18:02 ` [PATCH v2 memstick: support for legacy sony memsticks Tejun Heo
2012-09-25 19:34 ` Maxim Levitsky
2012-09-25 19:40 ` Tejun Heo [this message]
2012-09-25 20:13 ` Maxim Levitsky
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