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. CHANGELOG ========= >From v3 (20250709015712.97099-1-emil@xxxxxxxxxxxxxxx) ------------------------------------------------------ - 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@xxxxxxxxxxxxxxx) ------------------------------------------------------ - 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@xxxxxxxxxxxxxxx) ------------------------------------------------------ - 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@xxxxxxxxxxxxxxx> Emil Tsalapatis (2): bpf/arena: add bpf_arena_reserve_pages kfunc selftests/bpf: add selftests for bpf_arena_reserve_pages kernel/bpf/arena.c | 43 +++++++ .../testing/selftests/bpf/bpf_arena_common.h | 3 + .../selftests/bpf/progs/verifier_arena.c | 106 ++++++++++++++++++ .../bpf/progs/verifier_arena_large.c | 98 ++++++++++++++++ 4 files changed, 250 insertions(+) -- 2.49.0
