Bug#913138: linux: I/O on md RAID 6 hangs completely

[Stanisław]

I suffer the same problem while running RAID1 with kernel 4.18.10-2.   I have 
found a hint in the Debian kernel mailing list, however, I haven't tested 
it yet:   "...Someone else suggested this might be related to using 
"blk-mq", so  could you try with these parameter:   dm_mod.use_blk_mq=0 
scsi_mod.use_blk_mq=0   Also, do you have laptop-mode-tools installed?   
Ben..."   Please, read:  lists.debian.org lists.debian.org  
lists.debian.org lists.debian.org  lists.debian.org lists.debian.org