linux-azure 4.15 fails to boot on Standard_M416s_v2 in Azure
Bug #1951924 reported by
Gauthier Jolly
This bug affects 1 person
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| linux-azure (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
| Bionic |
In Progress
|
Medium
|
Bartlomiej Zolnierkiewicz | ||
| linux-azure-4.15 (Ubuntu) |
Fix Committed
|
Undecided
|
Krzysztof Kozlowski | ||
| Bionic |
Fix Released
|
Undecided
|
Krzysztof Kozlowski | ||
Bug Description
To reproduce:
* start a bionic VM in azure:
az vm create --name bionic --resource-group test-bionic --image "Canonical:
* "downgrade" the kernel to 4.15 and delete the 5.4 kernel
* reboot (the machine should fail to boot)
The serial console logs can be found on the azure portal (boot diagnostic needs to be enabled for the VM first).
| Changed in linux-azure (Ubuntu): | |
| status: | New → Confirmed |
| Changed in linux-azure (Ubuntu Bionic): | |
| assignee: | nobody → Bartlomiej Zolnierkiewicz (bzolnier) |
| importance: | Undecided → Medium |
| status: | New → In Progress |
| Changed in linux-azure (Ubuntu): | |
| status: | Confirmed → Invalid |
| Changed in linux-azure-4.15 (Ubuntu): | |
| status: | New → In Progress |
| Changed in linux-azure-4.15 (Ubuntu Bionic): | |
| status: | New → In Progress |
| Changed in linux-azure-4.15 (Ubuntu): | |
| status: | In Progress → Fix Committed |
| assignee: | nobody → Krzysztof Kozlowski (krzk) |
| Changed in linux-azure-4.15 (Ubuntu Bionic): | |
| status: | In Progress → Fix Committed |
| assignee: | nobody → Krzysztof Kozlowski (krzk) |
| tags: | added: kernel-daily-bug |
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[SRU Justification]
[Impact]
Current linux-azure-4.15 kernel in bionic fails to boot Standard_M416s_v2 VM because of x2apic being disabled:
[ 0.000000] x2apic: IRQ remapping doesn't support X2APIC mode write_msr+ 0x8/0x30) disable. part.5+ 0x49/0x80 IR_x2apic+ 0x123/0x18c setup_apic_ routing+ 0x16/0x73 mode_init+ 0x84/0x91 time_init+ 0x24/0x2b 0x444/0x505 start_reservati ons+0x24/ 0x26 start_kernel+ 0x74/0x77 startup_ 64+0xa5/ 0xb0
[ 0.000000] unchecked MSR access error: WRMSR to 0x1b (tried to write 0x00000000fee00100) at rIP: 0xffffffff9325d1f8 (native_
[ 0.000000] Call Trace:
[ 0.000000] __x2apic_
[ 0.000000] enable_
[ 0.000000] default_
[ 0.000000] apic_intr_
[ 0.000000] x86_late_
[ 0.000000] start_kernel+
[ 0.000000] x86_64_
[ 0.000000] x86_64_
[ 0.000000] secondary_
[ 0.000000] x2apic disabled
[ 0.000000] Switched APIC routing to physical flat.
[Test Plan]
Run updated kernel (with x2apic support backported from linux-azure-5.4 kernel).
It should boot fine and display:
[ 0.000000] Setting APIC routing to physical x2apic.
[Where problems could occur]
Potentially x2apic may now be used on other VM instances.
[Other Info]
None.