[Makedumpfile PATCH v2 0/2] Fix refiltering when kaslr enabled

Pratyush Anand panand at redhat.com
Thu May 11 19:41:36 PDT 2017

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.



 - reading KERNELOFFSET from vmcoreinfo now instead of calculating it from

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  | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 erase_info.c   |  1 +
 makedumpfile.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 makedumpfile.h | 16 ++++++++++++++++
 4 files changed, 124 insertions(+), 2 deletions(-)


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