[PATCH v16 00/20] arm64 kexec kernel patches v16
takahiro.akashi at linaro.org
Thu May 12 21:55:15 PDT 2016
Thank you for reporting this issue.
On Thu, May 12, 2016 at 07:24:08PM +0100, Julien Grall wrote:
> Hello Geoff,
> On 14/04/16 22:21, Geoff Levand wrote:
> >This series adds the core support for kexec re-boot and kdump on ARM64. This
> >version of the series combines Takahiro's kdump patches with my kexec patches.
> >Please consider all patches for inclusion.
> >To load a second stage kernel and execute a kexec re-boot or to work with kdump
> >on ARM64 systems a series of patches to kexec-tools , which have not yet been
> >merged upstream, are needed. Please update to the latest if you have been using
> >an older version.
> >To examine vmcore (/proc/vmcore), you should use
> > - gdb v7.7 or later
> > - crash v7.1.1 or later
> I have been trying to use crash dump with your branch without much
> success on juno-r2:
> WARNING: could not find MAGIC_START!
> crash: cannot determine base kernel version
> crash: /root/vmlinux and /root/coredump.kernel do not match!
> Looking at the debug log (-p 5), the translation va -> pa computed
> by crash is wrong.
> The physical address expected is 0x80a76b28, but crash return 0x88a76b28.
Yeah, this is due to Ard's KASLR patches (especially, f9040773b7bb: "arm64:
move kernel image to base of vmalloc area").
Now that the kernel image (and so all the kernel symbols) is located
in the vmalloc area, which is below PAGE_OFFSET, we can't use liner mapping
conversion for va -> pa in order to access kernel data in the core image.
I'm sure that the image (/proc/vmcore) is still sane, and we will have
to fix a user-space tool, i.e. crash.
The good news is that I've already confirmed that we could read the core
image successfully by adding a bit nasty hack to the tool.
I'll let you know once a refined patch gets ready.
Thanks for your patience,
> I am using crash built from  and the panic has been created using
> Also, crash dump seems to always report that Xen is running even
> when KVM was in used (see logs ) below.
> Lastly, crash fails with an error after a couple of minutes (see logs ).
> How you seen such errors during your testing?
>  https://github.com/crash-utility/crash
>  http://pastebin.com/wC8w44SN
> Julien Grall
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