diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 82f2da71eb35d..ea21e008bf856 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2664,6 +2664,12 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, if (opcode == BPF_CALL) { if (insn->src_reg == BPF_PSEUDO_CALL) return -ENOTSUPP; + /* kfunc with imm==0 is invalid and fixup_kfunc_call will + * catch this error later. Make backtracking conservative + * with ENOTSUPP. + */ + if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && insn->imm == 0) + return -ENOTSUPP; /* regular helper call sets R0 */ *reg_mask &= ~1; if (*reg_mask & 0x3f) {