Comment 6 for bug 2045384

Confirmed fixed in linux/5.15.0-94.104 using the itrue-mqtest-provider and itrue-mqtest-client snaps.

Test procedure:

sudo snap install itrue-mqtest-provider itrue-mqtest-client
sudo snap connect itrue-mqtest-client:itrue-mqtest-all-perms itrue-mqtest-provider:itrue-mqtest-all-perms
sudo snap connect itrue-mqtest-client:itrue-mqtest-default itrue-mqtest-provider:itrue-mqtest-default
sudo snap connect itrue-mqtest-client:itrue-mqtest-ro itrue-mqtest-provider:itrue-mqtest-ro
sudo snap connect itrue-mqtest-client:itrue-mqtest-rw itrue-mqtest-provider:itrue-mqtest-rw

Before upgrading (on kernel 5.15.0-1048-kvm):

ubuntu@concise-pangolin:~$ sudo itrue-mqtest-provider
MQ "/test-default" failed: File exists
ubuntu@concise-pangolin:~$ sudo itrue-mqtest-client.all
MQ "/test-all-perms" failed: Operation not permitted
Test failed

After upgrading (5.15.0-94-generic):

(in first terminal)
ubuntu@concise-pangolin:~$ sudo itrue-mqtest-provider
MQ "/test-default" created
MQ "/test-ro" created
MQ "/test-rw" created
MQ "/test-all-perms" created
MQ "/test-default": 0xDEADBEEF
MQ "/test-all-perms": 0xDEADBEEF

(in second terminal)
ubuntu@concise-pangolin:~$ sudo itrue-mqtest-client.default
Test succeeded
ubuntu@concise-pangolin:~$ sudo itrue-mqtest-client.all
Test succeeded