On 3/11/20 5:25 pm, Ulf Hansson wrote:
> On Wed, 28 Oct 2020 at 12:20, Veerabhadrarao Badiganti
> <vbadigan@xxxxxxxxxxxxxx> wrote:
>>
>> The commit bbdc74dc19e0 ("mmc: block: Prevent new req entering queue
>> after its cleanup") has introduced this change but it got moved after
>> del_gendisk() with commit 57678e5a3d51 ("mmc: block: Delete gendisk
>> before cleaning up the request queue").
>
> This isn't the first time we have spotted errors in this path. Seems
> like a difficult path to get correct. :-)
>
>>
>> It is blocking reboot with below Call stack().
>>
>> INFO: task reboot:3086 blocked for more than 122 seconds.
>> __schedule
>> schedule
>> schedule_timeout
>> io_schedule_timeout
>> do_wait_for_common
>> wait_for_completion_io
>> submit_bio_wait
>> blkdev_issue_flush
>> ext4_sync_fs
>> __sync_filesystem
>> sync_filesystem
>> fsync_bdev
>> invalidate_partition
>> del_gendisk
>> mmc_blk_remove_req
>> mmc_blk_remove
>> mmc_bus_remove
>> device_release_driver_internal
>> device_release_driver
>> bus_remove_device
>> device_del
>> mmc_remove_card
>> mmc_remove
>> mmc_stop_host
>> mmc_remove_host
>> sdhci_remove_host
>> sdhci_msm_remove
>
> Why do you call sdhci_msm_remove() from the shutdown callback? What
> specific operations do you need to run in the shutdown path for sdhci
> msm?
Yes, the problem is that upper layers, like the mmc block driver, have
already shut down, so doing operations like remove will get into deadlocks.
>
> The important part should be to do a graceful shutdown of the card
> (and the block device) - is there anything else?
>
> Or you are just using the shutdown callback as a simple way to trigger
> this problem? Could unbinding the driver trigger the same issue?
>
>> sdhci_msm_shutdown
>> platform_drv_shutdown
>> device_shutdown
>> kernel_restart_prepare
>> kernel_restart
>>
>> So bringing this change back.
>>
>> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>
>> ---
>>
>> I'm observing this issue 100% of the time with shutdown callback added to sdhci-msm driver.
>> I'm trying on 5.4 kernel with ChromeOS.
>>
>> Please let me know if this can be fixed in a better way.
>
> I don't know yet, but I will have a closer look. Let's also see if
> Adrian has some thoughts.
>
> Kind regards
> Uffe
>
>> ---
>>
>> drivers/mmc/core/block.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
>> index 8d3df0be0355..76dbb2b8a13b 100644
>> --- a/drivers/mmc/core/block.c
>> +++ b/drivers/mmc/core/block.c
>> @@ -2627,6 +2627,7 @@ static void mmc_blk_remove_req(struct mmc_blk_data *md)
>> * from being accepted.
>> */
>> card = md->queue.card;
>> + blk_set_queue_dying(md->queue.queue);
>> if (md->disk->flags & GENHD_FL_UP) {
>> device_remove_file(disk_to_dev(md->disk), &md->force_ro);
>> if ((md->area_type & MMC_BLK_DATA_AREA_BOOT) &&
>> --
>> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
>>
