Re: [printk] 18a2dc6982: ltp.kmsg01.fail

[Sergey Senozhatsky]

On (20/07/09 15:14), kernel test robot wrote:
[..]

Took me a while to find the FAIL-ed test:

> kmsg01.c:393: INFO: TEST: read returns EPIPE when messages get overwritten
> kmsg01.c:398: INFO: first seqno: 0
> kmsg01.c:411: INFO: first seqno now: 881
> kmsg01.c:425: FAIL: read returned: 77: SUCCESS (0)

So this is seq number related
https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/logging/kmsg/kmsg01.c#L383

LTP writes a gazillion (roughly, maybe a bit less than that)
filler messages to /dev/kmsg in order to cause logbuf overlap:
...
19490 [  172.301584] LTP kmsg01 FILLER MESSAGE TO OVERWRITE OTHERS
19491 [  172.308730] LTP kmsg01 FILLER MESSAGE TO OVERWRITE OTHERS
19492 [  172.313852] LTP kmsg01 FILLER MESSAGE TO OVERWRITE OTHERS
19493 [  172.320988] LTP kmsg01 FILLER MESSAGE TO OVERWRITE OTHERS
19494 [  172.325618] LTP kmsg01 FILLER MESSAGE TO OVERWRITE OTHERS
...

	-ss