On Apr 14, 2023 / 08:09, Chaitanya Kulkarni wrote: > On 4/14/2023 12:36 AM, Shin'ichiro Kawasaki wrote: > > Hello Bart, > > > > Recently, I built a new blktests trial environment on QEMU. With this > > environment, I observe scsi/007 failure. FYI, let me share blktests output [1] > > and kernel message [2]. > > > > I found the failure depends on kernel configs for debug such as KASAN. When I > > enable KASAN, the test case fails. When I disable KASAN, the test case passes. > > It looks that the failure depends on the slow kernel (and/or slow machine). > > > > The test case sets 1 second to the block layer timeout to trigger the SCSI error > > handler. It also sets 3 seconds to scsi_debug delay assuming the error handler > > completes before the 3 seconds. From the kernel message, it looks that the error > > handler takes longer than the 3 seconds delay, so I/O completes as success > > before the error handler completion. This I/O success is not expected then the > > test case fails. As a trial, I extended the scsi_debug delay time to 10 seconds, > > then I observed the test case passes. > > > > Do you expect the I/O success by slow SCSI error handler? If so, the test case > > needs improvement by extending the scsi_debug delay time. > > > > > > I faced the same problem, but increased timeout it is passing :- Good to know that I'm not the only one seeing this issue :) [snip] > > echo "I/O timeout = $(<"/sys/class/block/$dev/queue/io_timeout")" > >>"$FULL" # Change > the scsi_debug delay to 3 seconds. > - delay_s=3 > > + delay_s=10 Yes, I did similar trial and observed the test case passes. While I tried it, I observed that longer delay time is required when I add more kernel debug options (KASAN, lock related options, etc). So, delay extension to 10 seconds may not be enough to cover slower kernels or slower systems. I guess the test case will need some time measurement to decide the delay time good for the system. But before discussing such test case fix, I wanted to confirm that the delay time extension is the right fix approach.
