* register B - not null
* for JNE A, B, ... - A is not null in the false branch;
* for JEQ A, B, ... - A is not null in the true branch.
+ *
+ * Since PTR_TO_BTF_ID points to a kernel struct that does
+ * not need to be null checked by the BPF program, i.e.,
+ * could be null even without PTR_MAYBE_NULL marking, so
+ * only propagate nullness when neither reg is that type.
*/
if (!is_jmp32 && BPF_SRC(insn->code) == BPF_X &&
__is_pointer_value(false, src_reg) && __is_pointer_value(false, dst_reg) &&
- type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type)) {
+ type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type) &&
+ base_type(src_reg->type) != PTR_TO_BTF_ID &&
+ base_type(dst_reg->type) != PTR_TO_BTF_ID) {
eq_branch_regs = NULL;
switch (opcode) {
case BPF_JEQ: