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-rw-r--r--kernel/bpf/verifier.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 82f2da71eb35..ea21e008bf85 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) {