# VERIFICATION JAMMY This verification is using a jammy 5.15.0-1055 kernel on a focal machine. To reproduce this issue a special azure instance is required and currently I have access to a focal vm.
root@jo-twosla:/home/ubuntu# uname -rv 5.15.0-1055-azure #63~20.04.1-Ubuntu SMP Thu Jan 18 15:30:26 UTC 2024 root@jo-twosla:/home/ubuntu# lspci 0001:00:00.0 3D controller: NVIDIA Corporation TU104GL [Tesla T4] (rev a1) 3240:00:02.0 Ethernet controller: Mellanox Technologies MT27710 Family [ConnectX-4 Lx Virtual Function] (rev 80) root@jo-twosla:/home/ubuntu# echo '1' > /sys/bus/pci/devices/0001:00:00.0/remove root@jo-twosla:/home/ubuntu# lspci 3240:00:02.0 Ethernet controller: Mellanox Technologies MT27710 Family [ConnectX-4 Lx Virtual Function] (rev 80) The gpu is successfully removed without the vm crashing. ** Tags removed: verification-needed-jammy-linux-azure ** Tags added: verification-done-jammy-linux-azure -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-azure in Ubuntu. https://bugs.launchpad.net/bugs/2042568 Title: Azure - Kernel crashes when removing gpu from pci Status in linux-azure package in Ubuntu: Invalid Status in linux-azure source package in Jammy: Fix Committed Status in linux-azure source package in Lunar: Fix Committed Bug description: [Description] On a VM on Azure with a Tesla gpu it was noticed that when removing the gpu from the pci the vm would crash. In case the nvidia drivers are loaded, the machine won't crash. Instead the removing process will hang and the machine will crash on reboot. This is related to bug [1]. The bug reported in [1] regards another driver but the root cause is the same. It is still investigated whether this is a bug in pci, or it is a bug of various drivers on how they use pci. For this case we have identified that removing commit [2] prevents the kernel crashes. Azure has requested to revert this commit, at least for the time being. This commit is not in upstream, so it just need to be reverted from Ubuntu kernels. [Test Case] On an Azure vm with a gpu : # echo '1' > /sys/bus/pci/devices/0001:00:00.0/remove where '0001:00:00.0' the pci address of the gpu. The vm will crash. [Where things could go wrong] The commit to be reverted was included in a patchset to address lp bugs https://bugs.launchpad.net/bugs/2023071 and https://bugs.launchpad.net/bugs/2023594 However this commit just reduces boot time and removing shall not introduce any regressions. Side effects will be increase in the boot time. [Other] Only Ubuntu azure kernels are affected : - Jammy 5.15 - Lunar 6.2 Focal is also affected since it's using 5.15 kernel. This commit does not appear in Mantic 6.5 kernel. [1] https://bugzilla.kernel.org/show_bug.cgi?id=215515 [2] https://git.launchpad.net/~canonical-kernel/ubuntu/+source/linux-azure/+git/jammy/commit/?h=Ubuntu-azure-5.15.0-1043.50&id=75af0c10b3703400890d314d1d91d25294234a81 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/2042568/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
