Hello Alan, I noticed that recently nvme/039 fails on my system occasionally (around 40%). The failure messages are as follows: nvme/039 => nvme0n1 (test error logging) [failed] runtime 0.176s ... 0.167s --- tests/nvme/039.out 2023-04-06 10:11:07.925670528 +0900 +++ /home/shin/Blktests/blktests/results/nvme0n1/nvme/039.out.bad 2023-04-10 20:15:07.679538017 +0900 @@ -1,5 +1,2 @@ Running nvme/039 - Read(0x2) @ LBA 0, 1 blocks, Unrecovered Read Error (sct 0x2 / sc 0x81) DNR - Read(0x2) @ LBA 0, 1 blocks, Unknown (sct 0x3 / sc 0x75) DNR - Write(0x1) @ LBA 0, 1 blocks, Write Fault (sct 0x2 / sc 0x80) DNR Test complete nvme/039 => nvme0n1 (test error logging) [failed] runtime 0.167s ... 0.199s --- tests/nvme/039.out 2023-04-06 10:11:07.925670528 +0900 +++ /home/shin/Blktests/blktests/results/nvme0n1/nvme/039.out.bad 2023-04-10 20:15:09.114539650 +0900 @@ -1,5 +1,4 @@ Running nvme/039 - Read(0x2) @ LBA 0, 1 blocks, Unrecovered Read Error (sct 0x2 / sc 0x81) DNR Read(0x2) @ LBA 0, 1 blocks, Unknown (sct 0x3 / sc 0x75) DNR Write(0x1) @ LBA 0, 1 blocks, Write Fault (sct 0x2 / sc 0x80) DNR Test complete It looks that expected error messages were not reported. I suspect that the time duration is too short between error injection enable and I/O to trigger the error. With the one line change below to add wait after the error injection enable, the failures disappear. Do you think such wait is the valid fix? tests/nvme/rc | 1 + 1 file changed, 1 insertion(+) diff --git a/tests/nvme/rc b/tests/nvme/rc index 210a82a..7043c23 100644 --- a/tests/nvme/rc +++ b/tests/nvme/rc @@ -652,6 +652,7 @@ _nvme_enable_err_inject() echo "$4" > /sys/kernel/debug/"$1"/fault_inject/dont_retry echo "$5" > /sys/kernel/debug/"$1"/fault_inject/status echo "$6" > /sys/kernel/debug/"$1"/fault_inject/times + sleep 0.1 } _nvme_disable_err_inject() -- 2.39.2