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Hung tasks seen during ONTAP SFOs - Coggle Diagram
Hung tasks seen during ONTAP SFOs
observation
dm-mpath
io hang in blk-wbt
req with ->end_io
scsi
no normal io observed
only pt requests are found after hang
req with ->end_io
lots of them are from multipathd
some from scan lun
some from alua_rtpg_work
facts
sbitmap fixes merged to -186.el9
reported on cs9 -252.el9
not see in -162.el9(9.1)
?
dm-rq over scsi
scsi driver: lpfc
possible reasons
STS_DEV_RESOURCE
->end_io change
added in -186
rhel9.2-block-update-v6.1
final results
hctx->run_work is pending
forget to check this data structure
big lesson
root cause
lpfc ->queuecommand() blocks
dm-rq io hang story
no path
waiting for path to become active
path lookup hang
scsi TUR command