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From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org, Yi Zhang <yi.zhang@redhat.com>,
	Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH V3 0/2] block: fix race between adding wbt and normal IO
Date: Wed, 16 Jun 2021 22:11:35 +0800	[thread overview]
Message-ID: <YMoGlzLE2kUyaHlC@T590> (raw)
In-Reply-To: <YMfQSAT4hMDmdumY@T590>

On Tue, Jun 15, 2021 at 05:55:20AM +0800, Ming Lei wrote:
> On Wed, Jun 09, 2021 at 09:58:20AM +0800, Ming Lei wrote:
> > Hello,
> > 
> > Yi reported several kernel panics on:
> > 
> > [16687.001777] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
> > ...
> > [16687.163549] pc : __rq_qos_track+0x38/0x60
> > 
> > or
> > 
> > [  997.690455] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
> > ...
> > [  997.850347] pc : __rq_qos_done+0x2c/0x50
> > 
> > Turns out it is caused by race between adding wbt and normal IO.
> > 
> > Fix the issue by freezing request queue when adding/deleting rq qos.
> > 
> > V3:
> > 	- use ->queue_lock for protecting concurrent adding/deleting rqos on
> > 	  same queue
> > 
> > V2:
> > 	- switch to the approach of freezing queue, which is more generic
> > 	  than V1.
> > 
> > 
> > 
> > Ming Lei (2):
> >   block: fix race between adding/removing rq qos and normal IO
> >   block: mark queue init done at the end of blk_register_queue
> > 
> >  block/blk-rq-qos.h | 24 ++++++++++++++++++++++++
> >  block/blk-sysfs.c  | 29 +++++++++++++++--------------
> >  2 files changed, 39 insertions(+), 14 deletions(-)
> > 
> > Cc: Yi Zhang <yi.zhang@redhat.com>
> > Cc: Bart Van Assche <bvanassche@acm.org>
> 
> Hello Jens,
> 
> Any chance to merge the fixes if you are fine?

Hi Jens,

Yi finds that the issue can be triggered in his more tests, and
has escalate it in RH BZ, can we fix the issue?


Thanks,
Ming


  reply	other threads:[~2021-06-16 14:12 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-09  1:58 Ming Lei
2021-06-09  1:58 ` [PATCH V3 1/2] block: fix race between adding/removing rq qos " Ming Lei
2021-06-09 20:05   ` Bart Van Assche
2021-06-09  1:58 ` [PATCH V3 2/2] block: mark queue init done at the end of blk_register_queue Ming Lei
2021-06-09 20:09   ` Bart Van Assche
2021-06-10  0:45 ` [PATCH V3 0/2] block: fix race between adding wbt and normal IO Yi Zhang
2021-06-14 21:55 ` Ming Lei
2021-06-16 14:11   ` Ming Lei [this message]
2021-06-16 14:42 ` Jens Axboe

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