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?
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
>
