Azure Meraki vMX panic

Question

panic-capture-Azure-vMX.PNG

Problem:

• The Meraki vMX instance (based on Linux 4.4.177) panics and enters into crash kernel about 4 minutes into reboot.
• This happens definitely when we perform REDEPLOY operation from the Azure portal and always reproducible
• Found these patches Microsoft Azure Linux Kernel - specifically 0006-Drivers-hv-utils-fix-kvp-vss-call-traces.patch which seems most appropriate for the issue - can see similar stack trace (check the attachment)
• The problem is that the patch has to be applied manually - which I did but the build fails as hv_util.c makes reference to hyperv_cs variable of the type struct clocksource.
• This variable hyperv_cs is defined in arch/x86/kernel/cpu/mshyperv.c as a static variable and hence the build fails

Question:

• For resolving the problem, am I using the correct patch ?
• Is this patch ready to be used or it is missing some additions/modifications ? As it can be seen clearly that the patch cannot be compiled as clocksource variable is static scope within the source file arch/x86/kernel/cpu/mshyperv.c
• Has this patch been tested ?
• Or we need to use some other patch ?

Any help is highly appreciated

Answer 1

Hello Srihari Parimi (sriparim)

Q.For resolving the problem, am I using the correct patch ?

It appears that you believe this patch is the most appropriate for the issue you are encountering, but the build failure suggests that there may be compatibility issues or missing modifications.

Q.Is this patch ready to be used or it is missing some additions/modifications ? As it can be seen clearly that the patch cannot be compiled as clocksource variable is static scope within the source file arch/x86/kernel/cpu/mshyperv.c

Based on the information you provided, it seems that the patch cannot be compiled as is due to the use of the hyperv_cs variable, which is defined as a static variable in another source file. It's possible that the patch needs additional modifications or additions to work correctly.

Q.Has this patch been tested?
Not sure whether this specific patch has been tested. However, it's common for patches to be developed and shared within the open-source community, so it may have been tested by others.

Q.Do you need to use some other patch?
It's possible that a different patch or solution may be more appropriate for resolving the issue you are encountering.

I would recommend you to post this issue in relevant communities, such as the Linux kernel development community or the Meraki support team, for further guidance.

Hope this helps.