kernel/tools/testing/selftests/bpf/progs/verifier_precision.c, branch linux-rolling-stable

bpf: disable and remove registers chain based liveness

2025-09-19T16:27:23Z

Remove register chain based liveness tracking: - struct bpf_reg_state->{parent,live} fields are no longer needed; - REG_LIVE_WRITTEN marks are superseded by bpf_mark_stack_write() calls; - mark_reg_read() calls are superseded by bpf_mark_stack_read(); - log.c:print_liveness() is superseded by logging in liveness.c; - propagate_liveness() is superseded by bpf_update_live_stack(); - no need to establish register chains in is_state_visited() anymore; - fix a bunch of tests expecting "_w" suffixes in verifier log messages. Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20250918-callchain-sensitive-liveness-v3-9-c3cd27bacc60@gmail.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests for BPF_NEG range tracking logic

2025-06-25T22:12:18Z

BPF_REG now has range tracking logic. Add selftests for BPF_NEG. Specifically, return value of LSM hook lsm.s/socket_connect is used to show that the verifer tracks BPF_NEG(1) falls in the [-4095, 0] range; while BPF_NEG(100000) does not fall in that range. Signed-off-by: Song Liu Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20250625164025.3310203-3-song@kernel.org Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests with stack ptr register in conditional jmp

2025-05-27T21:09:12Z

Add two tests: - one test has 'rX r10' where rX is not r10, and - another test has 'rX rY' where rX and rY are not r10 but there is an early insn 'rX = r10'. Without previous verifier change, both tests will fail. Signed-off-by: Yonghong Song Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250524041340.4046304-1-yonghong.song@linux.dev

selftests/bpf: Use CAN_USE_LOAD_ACQ_STORE_REL when appropriate

2025-05-09T17:05:27Z

Instead of open-coding the conditions, use '#ifdef CAN_USE_LOAD_ACQ_STORE_REL' to guard the following tests: verifier_precision/bpf_load_acquire verifier_precision/bpf_store_release verifier_store_release/* Note that, for the first two tests in verifier_precision.c, switching to '#ifdef CAN_USE_LOAD_ACQ_STORE_REL' means also checking if '__clang_major__ >= 18', which has already been guaranteed by the outer '#if' check. Acked-by: Björn Töpel Reviewed-by: Pu Lehui Tested-by: Björn Töpel # QEMU/RVA23 Signed-off-by: Peilin Ye Link: https://lore.kernel.org/r/45d7e025f6e390a8ff36f08fc51e31705ac896bd.1746588351.git.yepeilin@google.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Add selftests for load-acquire and store-release instructions

2025-03-15T18:48:29Z

Add several ./test_progs tests: - arena_atomics/load_acquire - arena_atomics/store_release - verifier_load_acquire/* - verifier_store_release/* - verifier_precision/bpf_load_acquire - verifier_precision/bpf_store_release The last two tests are added to check if backtrack_insn() handles the new instructions correctly. Additionally, the last test also makes sure that the verifier "remembers" the value (in src_reg) we store-release into e.g. a stack slot. For example, if we take a look at the test program: #0: r1 = 8; /* store_release((u64 *)(r10 - 8), r1); */ #1: .8byte %[store_release]; #2: r1 = *(u64 *)(r10 - 8); #3: r2 = r10; #4: r2 += r1; #5: r0 = 0; #6: exit; At #1, if the verifier doesn't remember that we wrote 8 to the stack, then later at #4 we would be adding an unbounded scalar value to the stack pointer, which would cause the program to be rejected: VERIFIER LOG: ============= ... math between fp pointer and register with unbounded min value is not allowed For easier CI integration, instead of using built-ins like __atomic_{load,store}_n() which depend on the new __BPF_FEATURE_LOAD_ACQ_STORE_REL pre-defined macro, manually craft load-acquire/store-release instructions using __imm_insn(), as suggested by Eduard. All new tests depend on: (1) Clang major version >= 18, and (2) ENABLE_ATOMICS_TESTS is defined (currently implies -mcpu=v3 or v4), and (3) JIT supports load-acquire/store-release (currently arm64 and x86-64) In .../progs/arena_atomics.c: /* 8-byte-aligned */ __u8 __arena_global load_acquire8_value = 0x12; /* 1-byte hole */ __u16 __arena_global load_acquire16_value = 0x1234; That 1-byte hole in the .addr_space.1 ELF section caused clang-17 to crash: fatal error: error in backend: unable to write nop sequence of 1 bytes To work around such llvm-17 CI job failures, conditionally define __arena_global variables as 64-bit if __clang_major__ < 18, to make sure .addr_space.1 has no holes. Ideally we should avoid compiling this file using clang-17 at all (arena tests depend on __BPF_FEATURE_ADDR_SPACE_CAST, and are skipped for llvm-17 anyway), but that is a separate topic. Acked-by: Eduard Zingerman Signed-off-by: Peilin Ye Link: https://lore.kernel.org/r/1b46c6feaf0f1b6984d9ec80e500cc7383e9da1a.1741049567.git.yepeilin@google.com Signed-off-by: Alexei Starovoitov

selftests/bpf: add edge case backtracking logic test

2023-11-10T04:11:20Z

Add a dedicated selftests to try to set up conditions to have a state with same first and last instruction index, but it actually is a loop 3->4->1->2->3. This confuses mark_chain_precision() if verifier doesn't take into account jump history. Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20231110002638.4168352-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov

selftests/bpf: precision tracking test for BPF_NEG and BPF_END

2023-11-02T05:54:28Z

As seen from previous commit that fix backtracking for BPF_ALU | BPF_TO_BE | BPF_END, both BPF_NEG and BPF_END require special handling. Add tests written with inline assembly to check that the verifier does not incorrecly use the src_reg field of BPF_NEG and BPF_END (including bswap added in v4). Suggested-by: Eduard Zingerman Signed-off-by: Shung-Hsi Yu Link: https://lore.kernel.org/r/20231102053913.12004-4-shung-hsi.yu@suse.com Signed-off-by: Alexei Starovoitov