On 2020-07-09, Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> wrote: > 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 Excellent test. Since the messages are above the expected average size, the dataring is wrapping before the descriptor ring. This means that the initial descriptors are still there, but their data is gone. Initially I would generate an EPIPE for this, but it was changed. Here is the thread [0] we had about this. I have some ideas how to correctly handle this. Let me try some alternatives and post a proposed solution. John Ogness [0] https://lkml.kernel.org/r/20200213090757.GA36551@xxxxxxxxxx _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
