A mutual customer is reporting ssh is not working on a Xenial based VM. This VM is running the 4.4 based Xenial kernel and not a custom linux-azure kernel.
After an investigation this is a known old signaling issue. The 4.4 based Xenial kernels require the following patch:
The patch is not in the upstream stable 4.4 tree, because it’s not needed there.
Compared to the upstream 4.4 tree, Ubuntu 4.4.0-124-generic integrated more hv patches from the mainline kernel, e.g. Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read(), so it must pick up the above patch.
A mutual customer is reporting ssh is not working on a Xenial based VM. This VM is running the 4.4 based Xenial kernel and not a custom linux-azure kernel.
After an investigation this is a known old signaling issue. The 4.4 based Xenial kernels require the following patch:
vmbus: fix missing signaling in hv_signal_on_read() (https:/ /git.kernel. org/pub/ scm/linux/ kernel/ git/stable/ linux.git/ commit/ ?id=13c5e977010 91f9b02ded0c688 09f8a6b08c747a).
The patch is not in the upstream stable 4.4 tree, because it’s not needed there.
Compared to the upstream 4.4 tree, Ubuntu 4.4.0-124-generic integrated more hv patches from the mainline kernel, e.g. Drivers: hv: vmbus: finally fix hv_need_ to_signal_ on_read( ), so it must pick up the above patch.
We checked the latest Ubuntu 4.4 kernel (https:/ /kernel. ubuntu. com/git/ ubuntu/ ubuntu- xenial. git/tree/ ?h=Ubuntu- 4.4.0-146. 172) and the patch is also absent there.
The patch (13c5e97701091f 9b02ded0c68809f 8a6b08c747a) can be cleanly cherry-picked into Ubuntu- 4.4.0-146. 172.