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) |
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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.