KB5065789 seems to break RDMA

[ichundes]

FYI, after Windows Update installed KB5065789 Preview I couldn't get any RDMA connections to work anymore, neither NVMe-oF or SMB-Direct. I had to uninstall the update to get it working again.

[yaroslav (staff)]

Many thanks for sharing!
Could it be something funny with the NIC driver and kernel?

[ichundes]

I'm not sure what causes it. It is with a ConnectX-5 card and i tried KB5065789 with the stock driver and with WinOF2, made no difference. Everything looked good, Get-SmbMultiChannelConnection showed RDMA True, but RDMA would not be used. StarNVMeoF_Ctrl was unable to discover the RDMA address from the IP.

[ichundes]

I just reinstalled the update for testing and sure enough, the connection is broken again:

Code: Select all

PS C:\Users\axel> Get-NetAdapter -Name "Ethernet 3"

Name                      InterfaceDescription                    ifIndex Status       MacAddress             LinkSpeed
----                      --------------------                    ------- ------       ----------             ---------
Ethernet 3                HPE InfiniBand EDR/Ethernet 100Gb ...#2      13 Up           B8-83-03-9E-25-D1       100 Gbps


PS C:\Users\axel> Get-SmbMultichannelConnection

Server Name Selected Client IP Server IP Client Interface Index Server Interface Index Client RSS Capable Client RDMA
                                                                                                          Capable
----------- -------- --------- --------- ---------------------- ---------------------- ------------------ -------------
ares.lan    True     10.8.0.55 10.8.0.40 13                     54                     False              True


PS C:\Users\axel> StarNVMeoF_Ctrl.exe discovery 10.8.0.40 10.8.0.55

StarNVMeoF Controller Application v 2.0.0.702
Our Miniport #7 (ver 2.0.702, lic:1)
Discovering of RDMA addr 10.8.0.40:4420 from 10.8.0.55...
        NET_LUID:       0x6008002000000
STAR_NVMEOF_IOCTL_DISCOVERY request failed (err 0, status 0xc0000225)!
PS C:\Users\axel>

[ichundes]

https://aka.ms/AAy5d5s

[yaroslav (staff)]

Thanks for your effort and for sharing.

[ichundes]

I got a new update "Cumulative Update for Windows 11 Version 24H2 for x64-based Systems (KB5066835) (26100.6899)" which seems to not be affected by this anymore.

[yaroslav (staff)]

Great news!
Your post helped me.