[dm-devel] bdev lost its queue

[Stefan Raspl <raspl linux vnet ibm com>]

We conducted a bunch tests where we used various ways to forcefully 
disconnect or temporarily disable DASD disks from an IBM System z 
machine. In the course we ran into a kernel panic in 
dm_table_unplug_all() (dm-table.c), specifically at

    struct request_queue *q = bdev_get_queue(dd->bdev);
    blk_unplug(q);

since the queue of the bdev was NULL.
Did anyone see a crash in this place before? And are there other disk 
drivers to can set their queue to NULL due to unplugging/outages or similar?

Best regards,
Stefan

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