Merge branch 'bpf-arena-add-kfunc-for-reserving-arena-memory'

Browse source

Emil Tsalapatis says:

====================
bpf/arena: Add kfunc for reserving arena memory

Add a new kfunc for BPF arenas that reserves a region of the mapping
to prevent it from being mapped. These regions serve as guards against
out-of-bounds accesses and are useful for debugging arena-related code.

>From v3 (20250709015712.97099-1-emil@etsalapatis.com)
------------------------------------------------------

- Added Acked-by tags by Yonghong.
- Replace hardcoded error numbers in selftests (Yonghong).
- Fixed selftest for partially freeing a reserved region (Yonghong).

>From v2 (20250702003351.197234-1-emil@etsalapatis.com)
------------------------------------------------------

- Removed -EALREADY and replaced with -EINVAL to bring error handling in
  line with the rest of the BPF code (Alexei).

>From v1 (20250620031118.245601-1-emil@etsalapatis.com)
------------------------------------------------------

- Removed the additional guard range tree. Adjusted tests accordingly.
  Reserved regions now behave like allocated regions, and can be
  unreserved using bpf_arena_free_pages(). They can also be allocated
  from userspace through minor faults. It is up to the user to prevent
  erroneous frees and/or use the BPF_F_SEGV_ON_FAULT flag to catch
  stray userspace accesses (Alexei).
- Changed terminology from guard pages to reserved pages (Alexei,
  Kartikeya).

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
====================

Link: https://patch.msgid.link/20250709191312.29840-1-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

...

This commit is contained in:

Alexei Starovoitov 2025-07-11 10:43:55 -07:00

parent ad97cb2ed0 9f9559f0ac

commit 2b1fd82cba

4 changed files with 250 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

43

kernel/bpf/arena.c

View file

3

tools/testing/selftests/bpf/bpf_arena_common.h

View file

106

tools/testing/selftests/bpf/progs/verifier_arena.c

View file

98

tools/testing/selftests/bpf/progs/verifier_arena_large.c

View file