[Makedumpfile PATCH v4 0/2] Fix refiltering when kaslr enabled

Atsushi Kumagai ats-kumagai at wm.jp.nec.com
Fri May 26 00:45:16 PDT 2017

Hello Pratyush,

I have nothing to comment anymore, thanks for your hard work.
I'll merge v4 patches into v1.6.2.

Atsushi Kumagai

>Hi All,
>We came across another failure in makedumpfile when kaslr is enabled. This
>failure occurs when we try re-filtering. We try to erase some symbol from a
>dumpfile which was copied/compressed from /proc/vmcore using makedumpfile.
>We have very limited symbol information in vmcoreinfo. So symbols to be
>erased may not be available in vmcoreinfo and we look for it in vmlinux.
>However,  symbol address from vmlinux is a static address which differs
>from run time address with KASLR_OFFSET. Therefore, reading any "virtual
>address of vmlinux" from vmcore is not possible.
>These patches finds runtime  KASLR offset and then calculates run time
>address of symbols read from vmlinux.
>Hatayama Daisuke also found some issue [1] when he was working with a
>sadump and virsh dump of a none kaslr kernel. Patch 2/2 of this series has
>been improved to take care of those issues as well.
> - reading KERNELOFFSET from vmcoreinfo now instead of calculating it from
>   _stext
> - Fixed initialization of info->file_vmcoreinfo
> - Improved page_offset calculation logic to take care of different dump
>   scenarios.
> - Removed info->kaslr_offset write to VMCOREINFO
>Pratyush Anand (2):
>  makedumpfile: add runtime kaslr offset if it exists
>  x86_64: calculate page_offset in case of re-filtering/sadump/virsh
>    dump
> arch/x86_64.c  | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++------
> erase_info.c   |  1 +
> makedumpfile.c | 46 +++++++++++++++++++++++++++++++++++++
> makedumpfile.h | 16 +++++++++++++
> 4 files changed, 128 insertions(+), 7 deletions(-)

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