How to detect rebooting into kexec'd kernel

How to detect rebooting into kexec'd kernel

[Philip Prindeville]

How do you tell you’re in the new kernel?

There doesn’t seem to be anything in /sys/kernel/ that indicates this.

I could parse /proc/cmdline for the absence of “crashkernel=“ for instance, but there are obvious pitfalls to that.

You’d think there would be a way for the kexec’d kernel to maintain some sort of marker making it obvious that this is the kexec’d kernel (especially if your system kernel and your crash kernel are the same, and only the cmdline arguments change).

Thanks,

-Philip


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Re: How to detect rebooting into kexec'd kernel

[Baoquan He]

For kdump kernel, check /proc/vmcore
kexec kernel, no way.

On 03/11/17 at 10:40am, Philip Prindeville wrote:
> How do you tell you’re in the new kernel?
> 
> There doesn’t seem to be anything in /sys/kernel/ that indicates this.
> 
> I could parse /proc/cmdline for the absence of “crashkernel=“ for instance, but there are obvious pitfalls to that.
> 
> You’d think there would be a way for the kexec’d kernel to maintain some sort of marker making it obvious that this is the kexec’d kernel (especially if your system kernel and your crash kernel are the same, and only the cmdline arguments change).
> 
> Thanks,
> 
> -Philip
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

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