Patchset [1] introduces maple tree data structure for linux, and the
modification on mm subsystem.
The main impact on crash utility, is the modification on vm_area_struct.
Patch [2][3] removed the rbtree and linked list iteration of
vm_area_struct, making it impossible for crash to iterate vma
in the traditional way. For example, we can observe the failing
of crash cmd vm/fuser on kernel which has integrated with patchset [1].
This patchset deals with the issue by porting and adapting
kernel's maple tree vma iteration code to crash utility. It has been
tested on linux-next-next-20220914 [4].
Patch 1: the pure copy-and-paste work, extracting related kernel
structures, functions, constants to crash.
Patch 2: minimal code modification for crash adaption, kernel
structures are kept for member resolving.
Patch 3: modification on crash memory.c to use the maple vma
iteration.
The idea is to make patch 1-3 a POC work.
Patch 4: Get rid of kernel structures by rewriting the structure
member resolving code into the crash way, aka change
"node->member" into "readmem(node) and OFFSET(member)"
Patch 5: print the added variables of offset/size table
Patch 6: Get rid of the compiling-time assgined arrays.
Patch 4-6 will make the POC work formal for use.
[1]:
https://lore.kernel.org/all/20220906194824.2110408-1-liam.howl...@oracle.com/
[2]:
https://github.com/oracle/linux-uek/commit/d19703645b80abe35dff1a88449d074b0b5b1bb1
[3]:
https://github.com/oracle/linux-uek/commit/91dee01f1ebb6b6587463b6ee6f7bbc4965f91d5
[4]:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/snapshot/linux-next-next-20220914.tar.gz
Tao Liu (6):
Port linux maple tree related files to crash
Maple tree kernel code modification for step 1
Introduce maple tree vma iteration to memory.c
Maple tree kernel code modification for step 2
Dump maple tree offset variables by help -o
Remove mt_slots and mt_pivots array assignment
Makefile | 12 +-
defs.h | 19 ++
maple_tree.c | 824 +++++++++++++++++++++++++++++++++++++++++++++++
maple_tree.h | 109 +++++++
maple_tree_vma.h | 34 ++
memory.c | 315 ++++++++++--------
symbols.c | 34 ++
xarray.h | 70 ++++
8 files changed, 1285 insertions(+), 132 deletions(-)
create mode 100644 maple_tree.c
create mode 100644 maple_tree.h
create mode 100644 maple_tree_vma.h
create mode 100644 xarray.h
--
2.33.1
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