Hi Sagi,

I was able to capture a bit more info. Again, because my computer 
freezes (i.e. no keyboard or mouse response) I could only take a picture 
of the screen (attached). This does say NULL pointer dereference.

To answer your questions:

Q) Does this happen if you directly connect to a normal nvme controller?
A) I still need to try this. All I know is that it doesn't happen when 
the controller returns OAES[31]=0.

Q) What is your target implementation? Is this the nvme target thatis 
built into Linux?
A) I work for Dell, and I'm on the same team as Douglas Farley and Erik 
Smith, whom I believe you've had discussions with. Dell is currently 
developing a Central Discovery Controller (CDC). That's the target I've 
been testing with. I need to find different targets I can test with but 
working from home makes it a bit difficult. I will check with my team 
tomorrow to see if I can connect to a different target.

Q) Can you share your kernel config file?
Q) Can you run gdb on vmlinux and share what this provides?
A) I'll get that tomorrow (both questions).

For the record, I compiled Fedora 33 kernel and ran it on my VM
and it doesn't happen. I also modified Linux nvme target to
report the same limits as your target and still it doesn't happen.
--
[  162.006049] nvme nvme0: Failed to read smart log (error 24577)
[  162.006060] nvme nvme0: queue_size 128 > ctrl sqsize 32, clamping down
[  162.006063] nvme nvme0: sqsize 32 > ctrl maxcmd 31, clamping down
[  162.006778] nvme nvme0: new ctrl: NQN 
"nqn.2014-08.org.nvmexpress.discovery", addr 192.168.123.1:8009
[  162.008939] nvme nvme0: Removing ctrl: NQN 
"nqn.2014-08.org.nvmexpress.discovery"
--

So something here seems to be specific to your env.

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