From: Christoph Hellwig <hch@lst.de>
To: Bart Van Assche <bvanassche@acm.org>
Cc: "Martin K . Petersen" <martin.petersen@oracle.com>,
"James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
Alan Stern <stern@rowland.harvard.edu>,
Stanley Chu <stanley.chu@mediatek.com>,
Ming Lei <ming.lei@redhat.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
stable <stable@vger.kernel.org>, Can Guo <cang@codeaurora.org>
Subject: Re: [PATCH v2 1/9] block: Fix a race in the runtime power management code
Date: Mon, 16 Nov 2020 18:14:35 +0100 [thread overview]
Message-ID: <20201116171435.GA22007@lst.de> (raw)
In-Reply-To: <20201116030459.13963-2-bvanassche@acm.org>
On Sun, Nov 15, 2020 at 07:04:51PM -0800, 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.
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2020-11-16 17:14 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-16 3:04 [PATCH v2 0/9] Rework runtime suspend and SCSI domain validation Bart Van Assche
2020-11-16 3:04 ` [PATCH v2 1/9] block: Fix a race in the runtime power management code Bart Van Assche
2020-11-16 17:14 ` Christoph Hellwig [this message]
2020-11-16 3:04 ` [PATCH v2 2/9] ide: Do not set the RQF_PREEMPT flag for sense requests Bart Van Assche
2020-11-16 17:14 ` Christoph Hellwig
2020-11-16 3:04 ` [PATCH v2 3/9] scsi: Pass a request queue pointer to __scsi_execute() Bart Van Assche
2020-11-16 17:16 ` Christoph Hellwig
2020-11-18 1:16 ` Can Guo
2020-11-16 3:04 ` [PATCH v2 4/9] scsi: Rework scsi_mq_alloc_queue() Bart Van Assche
2020-11-16 17:17 ` Christoph Hellwig
2020-11-16 18:01 ` Bart Van Assche
2020-11-20 1:36 ` Bart Van Assche
2020-11-18 1:15 ` Can Guo
2020-11-16 3:04 ` [PATCH v2 5/9] scsi: Do not wait for a request in scsi_eh_lock_door() Bart Van Assche
2020-11-16 17:18 ` Christoph Hellwig
2020-11-16 3:04 ` [PATCH v2 6/9] scsi_transport_spi: Make spi_execute() accept a request queue pointer Bart Van Assche
2020-11-16 17:18 ` Christoph Hellwig
2020-11-16 3:04 ` [PATCH v2 7/9] scsi_transport_spi: Freeze request queues instead of quiescing Bart Van Assche
2020-11-16 17:22 ` Christoph Hellwig
2020-11-16 17:51 ` Bart Van Assche
2020-11-16 3:04 ` [PATCH v2 8/9] block, scsi, ide: Only process PM requests if rpm_status != RPM_ACTIVE Bart Van Assche
2020-11-16 17:22 ` Christoph Hellwig
2020-11-17 16:00 ` [block, scsi, ide] 3e3b42fee6: kmsg.sd#:#:#:#:[sdf]Asking_for_cache_data_failed kernel test robot
2020-11-17 16:46 ` Bart Van Assche
2020-11-18 1:16 ` [LKP] " Philip Li
2020-11-18 1:13 ` [PATCH v2 8/9] block, scsi, ide: Only process PM requests if rpm_status != RPM_ACTIVE Can Guo
2020-11-18 9:08 ` Stanley Chu
2020-11-16 3:04 ` [PATCH v2 9/9] block: Do not accept any requests while suspended Bart Van Assche
2020-11-16 17:23 ` Christoph Hellwig
2020-11-18 1:12 ` Can Guo
2020-11-18 9:05 ` Stanley Chu
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