Re: blktests scsi/007 failure

[Chaitanya Kulkarni <chaitanyak@nvidia.com>]

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 :-

blktests (master) # ./check scsi/007 
                                                     scsi/007 (Trigger 
the SCSI error handler)                    [failed] 
                                       runtime    ...  38.529s 
 
                    --- tests/scsi/007.out      2022-07-18 
16:14:37.204230234 -0700 
              +++ /root/blktests/results/nodev/scsi/007.out.bad 
2023-04-14 01:03:26.518991337 -0700 
@@ -1,3 +1,3 @@ 
                                                      Running scsi/007 
 
                                  -Reading from scsi_debug failed 
 
               +Reading from scsi_debug succeeded 
 
Test complete 
                                                blktests (master) # vim 
tests/scsi/007
 
 
                                  blktests (master) # git diff 
 
               diff --git a/tests/scsi/007 b/tests/scsi/007 
 
index e7088a1..1aa3e03 100755 
                                                     --- 
a/tests/scsi/007 
                                                 +++ b/tests/scsi/007 
 
                              @@ -41,7 +41,7 @@ test() { 
 
                   echo 1 > "/sys/class/block/$dev/queue/io_timeout" 
 
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 
 
      freq=$(config_hz) 
 
jdelay=$((delay_s * "${freq}")) 
                                                     echo 
"CONFIG_HZ=${freq} jdelay=${jdelay}" >>"$FULL" 


blktests (master) # ./check scsi/007 
                                                     scsi/007 (Trigger 
the SCSI error handler)                    [passed] 
                                       runtime  21.264s  ...  21.267s 
 
                blktests (master) # 
 
blktests (master) #

you can give it a try to see if it fixes the problem ..

-ck