Hi TrueNAS Community,
I am reaching out to you in hope that someone else might have experienced a similar bug in their setup. I have now been hunting this issue since a couple weeks and originally, I even believed that my MacBook has a hardware issue (e.g. my device could also be a dud). However, recently I found some hints that the issues might be related to my specific TrueNAS set-up. I have also spent a good amount of time searching the web whether anyone else experiences the same issue but I did not find anything helpful so far. My issue is as follows:
When I am connected to my home network, I am experiencing sporadic kernel panics on my MacBook Air M3 15” with macOS Tahoe (currently I am on macOS 26.6.2). My TrueNAS system is on version 25.10.7 - Goldeye. The kernel panics are almost exclusively related to the “com.apple.filesystems.smbfs” driver and often show “[skywalk.reg.bufctl]: element modified after free” as immediate panic cause. They happen randomly during system usage, sometimes even while the device is in hibernation.
I have set-up a timemachine SMB share on TrueNAS and also configured timemachine on the Macbook - this works so far. Below you can find the configuration of my SMB service:
On TrueNAS I have only SMB enabled, no other fileshare service is active. I think it is also worth to note that my macOS username is identical to my TrueNAS SMB user - could this be an issue?
Today I could finally reproduce the issue on my MacBook with the help of Gemini: When I start a timemachine backup and concurrently scan file permissions on the NAS share, the Macbook panics after a couple minutes.
# Start a time machine backup
$ tmutil startbackup
# Scan file permissions on the NAS
$ sudo find "/Volumes/Backups of Macbook" -exec xattr -l {} + 2>/dev/null
I then created a nsmb.conf file and so far I can no longer reproduce the kernel panic:
$ cat << EOF | sudo tee /etc/nsmb.conf
[default]
mc_on=no
signing_required=no
dir_cache_off=yes
EOF
I think it is to early to state that this really fixed the issue, I will need to test this a little longer. However, even if it fixes the issue, it is not a nice fix since it is client side only. This is why I am reaching out to you, maybe I have missed something or someone else might know immediately how to fix this on TrueNAS side.
Thank you very much,
Michael