diff options
| author | Eduard Zingerman <eddyz87@gmail.com> | 2026-10-09 03:47:26 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-10-09 20:29:12 +0000 |
| commit | 2d903f95721a0e0084c8b671e09c1b9425b1a448 (patch) | |
| tree | d520b93608f32e81dc54190161655ed1197bf488 /kernel | |
| parent | c6477be1580445be005c8c249f00fc44eeca3190 (diff) | |
bpf: Record write effects for atomic operations in liveness.c
Atomic read-modify-write instructions are recorded as reads only,
omitting their stack write effects from the may_write masks needed
by SCEV.
Record both read and write accesses for atomic RMW operations. Keep
LOAD_ACQ read-only and STORE_REL write-only. Share the precise/imprecise
stack-access dispatch so both accesses use the same address handling.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://patch.msgid.link/20261009-scev-minimal-rebase-v3-8-bcba9bc53ac9@gmail.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/liveness.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/kernel/bpf/liveness.c b/kernel/bpf/liveness.c index b9b76684906e..ce74e3f16eef 100644 --- a/kernel/bpf/liveness.c +++ b/kernel/bpf/liveness.c @@ -1634,14 +1634,22 @@ static int record_load_store_access(struct bpf_verifier_env *env, break; case BPF_STX: if (BPF_MODE(insn->code) == BPF_ATOMIC) { - if (insn->imm == BPF_STORE_REL) - write = true; - else - read = true; - if (insn->imm == BPF_LOAD_ACQ) + switch (insn->imm) { + case BPF_LOAD_ACQ: ptr = &at[insn->src_reg]; - else + read = true; + break; + case BPF_STORE_REL: ptr = &at[insn->dst_reg]; + write = true; + break; + default: + /* ADD/AND/OR/XOR(+FETCH), XCHG, CMPXCHG */ + ptr = &at[insn->dst_reg]; + read = true; + write = true; + break; + } } else { ptr = &at[insn->dst_reg]; write = true; |