From: Hannes Reinecke <hare@suse.de>
To: Bart Van Assche <bvanassche@acm.org>,
"Martin K . Petersen" <martin.petersen@oracle.com>
Cc: "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
Ming Lei <ming.lei@redhat.com>,
linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
Alan Stern <stern@rowland.harvard.edu>,
Stanley Chu <stanley.chu@mediatek.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
stable <stable@vger.kernel.org>, Can Guo <cang@codeaurora.org>
Subject: Re: [PATCH v3 1/9] block: Fix a race in the runtime power management code
Date: Mon, 23 Nov 2020 07:46:37 +0100 [thread overview]
Message-ID: <adeb251b-bfda-e3c5-e098-4105c2835922@suse.de> (raw)
In-Reply-To: <20201123031749.14912-2-bvanassche@acm.org>
On 11/23/20 4:17 AM, Bart Van Assche wrote:
> With the current implementation the following race can happen:
> * blk_pre_runtime_suspend() calls blk_freeze_queue_start() and
> blk_mq_unfreeze_queue().
> * blk_queue_enter() calls blk_queue_pm_only() and that function returns
> true.
> * blk_queue_enter() calls blk_pm_request_resume() and that function does
> not call pm_request_resume() because the queue runtime status is
> RPM_ACTIVE.
> * blk_pre_runtime_suspend() changes the queue status into RPM_SUSPENDING.
>
> Fix this race by changing the queue runtime status into RPM_SUSPENDING
> before switching q_usage_counter to atomic mode.
>
> Acked-by: Alan Stern <stern@rowland.harvard.edu>
> Acked-by: Stanley Chu <stanley.chu@mediatek.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Cc: stable <stable@vger.kernel.org>
> Fixes: 986d413b7c15 ("blk-mq: Enable support for runtime power management")
> Signed-off-by: Can Guo <cang@codeaurora.org>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
> block/blk-pm.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
next prev parent reply other threads:[~2020-11-23 6:46 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 3:17 [PATCH v3 0/9] Rework runtime suspend and SCSI domain validation Bart Van Assche
2020-11-23 3:17 ` [PATCH v3 1/9] block: Fix a race in the runtime power management code Bart Van Assche
2020-11-23 6:46 ` Hannes Reinecke [this message]
2020-11-23 3:17 ` [PATCH v3 2/9] ide: Do not set the RQF_PREEMPT flag for sense requests Bart Van Assche
2020-11-23 6:47 ` Hannes Reinecke
2020-11-23 3:17 ` [PATCH v3 3/9] scsi: Pass a request queue pointer to __scsi_execute() Bart Van Assche
2020-11-23 3:17 ` [PATCH v3 4/9] scsi: Inline scsi_mq_alloc_queue() Bart Van Assche
2020-11-24 9:14 ` Christoph Hellwig
2020-11-24 9:49 ` Can Guo
2020-11-23 3:17 ` [PATCH v3 5/9] scsi: Do not wait for a request in scsi_eh_lock_door() Bart Van Assche
2020-11-23 3:17 ` [PATCH v3 6/9] scsi_transport_spi: Make spi_execute() accept a request queue pointer Bart Van Assche
2020-11-23 3:17 ` [PATCH v3 7/9] scsi_transport_spi: Freeze request queues instead of quiescing Bart Van Assche
2020-11-23 7:02 ` Hannes Reinecke
2020-11-24 5:09 ` Bart Van Assche
2020-11-24 7:13 ` Hannes Reinecke
2020-11-23 3:17 ` [PATCH v3 8/9] block, scsi, ide: Only process PM requests if rpm_status != RPM_ACTIVE Bart Van Assche
2020-11-23 3:17 ` [PATCH v3 9/9] block: Do not accept any requests while suspended Bart Van Assche
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