Hi,

I am using lttng-modules 2.12.5 with a 5.4.93 kernel on an aarch64 target. After creating a session I run

lttng enable-event -k block*

to enable all the block_ kernel events but when I run babeltrace on the generated traces I get a handful of

[warning] Unknown value 33 in enum.
...
...

with different values in place of 33. This does not happen with any other kernel event type

BabelTrace Trace Viewer and Converter 1.5.8

Also if I try to do a 'lttng view' on this session I can identify that this has something to do with the rwbs field as I get

[14:03:42.649719750] (+0.000005750) imx8qxpmek block_bio_remap: { cpu_id = 3 }, { dev = 187695200, sector = 2460080, nr_sector = 8, rwbs = ( <unknown> : container = 33 ), old_dev = 187695203, old_sector = 2105776 }
[14:03:42.649722125] (+0.000002375) imx8qxpmek block_bio_queue: { cpu_id = 3 }, { dev = 187695200, sector = 2460080, nr_sector = 8, rwbs = ( <unknown> : container = 33 ), tid = 428, comm = "jbd2/mmcblk1p3-" }
[14:03:42.649725000] (+0.000002875) imx8qxpmek block_bio_backmerge: { cpu_id = 3 }, { dev = 187695200, sector = 2460080, nr_sector = 8, rwbs = ( <unknown> : container = 33 ), tid = 428, comm = "jbd2/mmcblk1p3-" }
...
...

I believe <unknown> in the log points to a symptom? While for the events/container id that do not generate this warning I have in the same trace

[14:03:44.697572375] (+2.036943500) imx8qxpmek block_bio_remap: { cpu_id = 0 }, { dev = 187695200, sector = 9382032, nr_sector = 8, rwbs = ( "RWBS_FLAG_WRITE" : container = 1 ), old_dev = 187695206, old_sector = 278672 }
[14:03:44.697584375] (+0.000012000) imx8qxpmek block_bio_queue: { cpu_id = 0 }, { dev = 187695200, sector = 9382032, nr_sector = 8, rwbs = ( "RWBS_FLAG_WRITE" : container = 1 ), tid = 1609, comm = "kworker/u8:0" }
[14:03:44.697604250] (+0.000019875) imx8qxpmek block_getrq: { cpu_id = 0 }, { dev = 187695200, sector = 9382032, nr_sector = 8, rwbs = ( "RWBS_FLAG_WRITE" : container = 1 ), tid = 1609, comm = "kworker/u8:0" }

The interesting thing to note with the working events is that all of them have "RWBS_FLAG_WRITE" and no other types from https://github.com/lttng/lttng-modules/blob/stable-2.12/instrumentation/events/lttng-module/block.h#L39 which I would expect to see.

I am lost for hints as to what I need to look up... any help would be highly appreciated.

-- 
BR,
Awais