On Thu Jul 16, 2026 at 12:28 AM CEST, Ihor Solodrai wrote: > On 7/9/26 3:01 AM, Alexis Lothoré (eBPF Foundation) wrote:
[...] >> @@ -1984,6 +2000,10 @@ static int do_jit(struct bpf_verifier_env *env, >> struct bpf_prog *bpf_prog, int * >> EMIT_ENDBR(); >> >> ip = image + addrs[i - 1] + (prog - temp); >> + insn_idx = i - 1 + bpf_prog->aux->subprog_start; >> + accesses_stack_only = >> + env ? !env->insn_aux_data[insn_idx].non_stack_access : >> + false; > > I don't like how accesses_stack_only is a boolean argument to > emit_kasan_check(), that is only used for early return. > I can see not wanting to do > > if (!accesses_stack_only) > err = emit_kasan_check(...); > > on every call site, but a bool arg is even worse IMO. Yes, that was indeed the intent, but ok, I can get back to set the stack access check out of the function. [...] >> @@ -2626,7 +2662,17 @@ 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; > > nit > > IIUC the 3 comes from emit_mov_reg() above it (:2659), right? I was > thinking to suggest a comment, but well I figured it out from the > code, so others should too... Yes, that's indeed where it comes from (and this cost me quite some debugging time to spot that I was missing this offset !) > > Maybe instead of hardcoding 3 we could calculcate the diff > before/after the mov is emitted? ACK, I'll remove the hardcoded scalar and set it to (prog - *pprog) Alexis -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
