> diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> index b70cecfec179..a383ffc8f289 100644
> --- a/arch/x86/net/bpf_jit_comp.c
> +++ b/arch/x86/net/bpf_jit_comp.c
[ ... ]
> @@ -2605,14 +2640,14 @@ static int do_jit(struct bpf_verifier_env *env,
> struct bpf_prog *bpf_prog, int *
> }
> fallthrough;
> case BPF_STX | BPF_ATOMIC | BPF_W:
> - case BPF_STX | BPF_ATOMIC | BPF_DW:
> + case BPF_STX | BPF_ATOMIC | BPF_DW: {
> + bool is64 = BPF_SIZE(insn->code) == BPF_DW;
> + u32 real_src_reg = src_reg;
> + u32 real_dst_reg = dst_reg;
> + u8 *branch_target;
> if (insn->imm == (BPF_AND | BPF_FETCH) ||
> insn->imm == (BPF_OR | BPF_FETCH) ||
> insn->imm == (BPF_XOR | BPF_FETCH)) {
> - bool is64 = BPF_SIZE(insn->code) == BPF_DW;
> - u32 real_src_reg = src_reg;
> - u32 real_dst_reg = dst_reg;
> - u8 *branch_target;
>
> /*
> * Can't be implemented with a single x86 insn.
> @@ -2626,7 +2661,19 @@ static int do_jit(struct bpf_verifier_env *env, struct
> bpf_prog *bpf_prog, int *
> if (dst_reg == BPF_REG_0)
> real_dst_reg = BPF_REG_AX;
>
> + ip += 3;
> + }
> + if (!bpf_atomic_is_load_store(insn)) {
> + err = emit_kasan_check(env, &prog, real_dst_reg,
> + insn, ip, false,
> + accesses_stack_only);
> + if (err)
> + return err;
> branch_target = prog;
> + }
> + if (insn->imm == (BPF_AND | BPF_FETCH) ||
> + insn->imm == (BPF_OR | BPF_FETCH) ||
> + insn->imm == (BPF_XOR | BPF_FETCH)) {
> /* Load old value */
> emit_ldx(&prog, BPF_SIZE(insn->code),
> BPF_REG_0, real_dst_reg, insn->off);
This isn't a bug, but the FETCH-op check
insn->imm == (BPF_AND | BPF_FETCH) ||
insn->imm == (BPF_OR | BPF_FETCH) ||
insn->imm == (BPF_XOR | BPF_FETCH)
is now spelled out in two adjacent if blocks in this case, where it was
written once before the patch.
Could it be hoisted into a single local (e.g. bool is_fetch = ...) so the
two copies don't have to be kept in sync on later edits?
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/28510424881
