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From: Jens Axboe <axboe@kernel.dk>
To: Akinobu Mita <akinobu.mita@gmail.com>, linux-kernel@vger.kernel.org
Cc: Ming Lei <tom.leiming@gmail.com>, Tejun Heo <tj@kernel.org>,
	Keith Busch <keith.busch@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	Wanpeng Li <wanpeng.li@hotmail.com>
Subject: Re: [PATCH v4 0/7] blk-mq: fix race conditions on cpu hotplug handling
Date: Tue, 29 Sep 2015 11:31:52 -0600	[thread overview]
Message-ID: <560ACB08.9020806@kernel.dk> (raw)
In-Reply-To: <1443287365-4244-1-git-send-email-akinobu.mita@gmail.com>

On 09/26/2015 11:09 AM, Akinobu Mita wrote:
> This patchset addresses several race conditions on cpu hotplug handling
> for blk-mq.  All problems can be reproducible by the following script.
>
> while true; do
> 	echo 0 > /sys/devices/system/cpu/cpu1/online
> 	echo 1 > /sys/devices/system/cpu/cpu1/online
> done &
>
> while true; do
> 	modprobe -r null_blk
> 	modprobe null_blk queue_mode=2 irqmode=1
> 	sleep 0.1
> done
>
> * Changes from v3
> - Rebased to the latest kernel
> - Add Reviewed-by tags

I've reviewed the patches, looks good to me. I've skipped 6/7, as I 
think we should fix that as part of the percpu ref counting, and not 
handle it specifically in blk-mq. If we can't get that fix before 4.3 
wraps up, then we can revisit and put that in as well.

Thanks!

-- 
Jens Axboe


      parent reply	other threads:[~2015-09-29 17:32 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-26 17:09 [PATCH v4 0/7] blk-mq: fix race conditions on cpu hotplug handling Akinobu Mita
2015-09-26 17:09 ` [PATCH v4 1/7] blk-mq: avoid setting hctx->tags->cpumask before allocation Akinobu Mita
2015-09-26 18:12   ` Christoph Hellwig
2015-09-26 17:09 ` [PATCH v4 2/7] blk-mq: fix sysfs registration/unregistration race Akinobu Mita
2015-09-29  6:51   ` Christoph Hellwig
2015-09-26 17:09 ` [PATCH v4 3/7] blk-mq: Fix use after of free q->mq_map Akinobu Mita
2015-09-29  6:52   ` Christoph Hellwig
2015-10-05 23:50     ` Akinobu Mita
2015-10-06  9:43       ` Christoph Hellwig
2015-09-26 17:09 ` [PATCH v4 4/7] blk-mq: fix q->mq_usage_counter access race Akinobu Mita
2015-09-29  6:53   ` Christoph Hellwig
2015-09-26 17:09 ` [PATCH v4 5/7] blk-mq: avoid inserting requests before establishing new mapping Akinobu Mita
2015-09-29  6:54   ` Christoph Hellwig
2015-09-26 17:09 ` [PATCH v4 6/7] blk-mq: fix freeze queue race Akinobu Mita
2015-09-26 17:32   ` Tejun Heo
2015-09-27 13:06     ` Akinobu Mita
2015-09-28 14:48       ` Tejun Heo
2015-09-29  6:55         ` Christoph Hellwig
2015-09-29 15:01         ` Jens Axboe
2015-09-29 15:03           ` Tejun Heo
2015-09-29 21:50             ` Tejun Heo
2015-09-30 10:32               ` Akinobu Mita
2015-09-26 17:09 ` [PATCH v4 7/7] blk-mq: fix deadlock when reading cpu_list Akinobu Mita
2015-09-29  6:58   ` Christoph Hellwig
2015-09-29 17:31 ` Jens Axboe [this message]

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