[PATCH v23 0/9] arm64: add kdump support

On Mon, Aug 01, 2016 at 11:51:12AM +0530, Pratyush Anand wrote:

Hi Takahiro,

On 01/08/2016:01:37:26 PM, AKASHI Takahiro wrote:

quoted

Pratyush,

On Fri, Jul 29, 2016 at 10:43:00PM +0530, Pratyush Anand wrote:

quoted

Hi Ruslan,

On 29/07/2016:07:26:03 PM, Ruslan Bilovol wrote:

quoted

Hi,

On Tue, Jul 26, 2016 at 11:09 AM, AKASHI Takahiro
[off-list ref] wrote:

quoted

On Tue, Jul 26, 2016 at 04:56:51PM +0900, AKASHI Takahiro wrote:

quoted

This patch series adds kdump support on arm64.

To load a crash-dump kernel to the systems, a series of patches to
kexec-tools, which have not yet been merged upstream, are needed.
Please pick Geoff's kexec patches [1] and my kdump patches [2].

To examine vmcore (/proc/vmcore) on a crash-dump kernel, you can use
  - crash utility (coming v7.1.6 or later) [3]
    (Necessary patches have already been queued in the master.)

[1]  http://lists.infradead.org/pipermail/kexec/2016-July/016532.html
[2]  TBD

See my kexec-tools patches in:
http://lists.infradead.org/pipermail/kexec/2016-July/016642.html

I tired this patch series with mentioned Geoff's kexec patches and
your kdump patches, but unfortunately it doesn't work for me.

While I can successfully load and kexec the kernel ('kexec --load' +
'kexec -e'), same combination of kernel+ramdisk+dtb doesn't boot
if I do kdump combination ('kexec -p' + sysrq crash), there is no
any output after sysrq crash trace.
Unfortunately I don't have any debugger here for deep investigation
of this issue.

Which type of image do you have? I did face issue with binary image which I
fixed in my branch, while elf would work fine for kdump as well.

Can you describe in more details, please?
I don't see any problems with either vmlinux or image
in my environment.

See kexec/crashdump-elf.c:FUNC()
We have:
223                 phdr->p_vaddr = phys_to_virt(elf_info, mstart);
Now, if we do not have page_offset then we will not have correct p_vaddr, and
then vmcore-dmesg/vmcore-dmesg.c:vaddr_to_offset() fails with

I don't see how this issue relates to Ruslan's case.

-Takahiro AKASHI

No program header covering vaddr 0xfffffc0008c312f0found kexec bug?

Fedora/RHEL kexec-tools saves vmcore only when dmesg save is OK.

I have updated [1] with the modification where --page-offset addition has been
moved to kdump binary image support patch.

[1] https://github.com/pratyushanand/kexec-tools.git : upstream_arm64_devel

~Pratyush