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

Atsushi Kumagai ats-kumagai at wm.jp.nec.com
Thu Apr 27 23:52:56 PDT 2017

Hello Pratyush,

Thanks for your report, I have received this.
I'm on vacation until Mar 8, I'll review it when I return from vacation.

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.
>Since, I am not an expert of x86, and these patches touch x86 part of
>makedumpfile, therefore I have CCed x86 experts. Please, provide your
>review comment and let me know if you think there could have been a better
>way to resolve this issue.
>Pratyush Anand (2):
>  makedumpfile: add runtime kaslr offset if it exists
>  x86_64: calculate page_offset in case of re-filtering
> arch/x86_64.c  | 45 +++++++++++++++++++++++++++++++++++++++++++--
> erase_info.c   |  1 +
> makedumpfile.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> makedumpfile.h | 15 +++++++++++++++
> 4 files changed, 103 insertions(+), 2 deletions(-)

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