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1// SPDX-License-Identifier: GPL-2.02 3#include "vmlinux.h"4#include <bpf/bpf_helpers.h>5#include "bpf_misc.h"6 7#ifndef __clang__8#pragma GCC diagnostic ignored "-Warray-bounds"9#endif10 11char _license[] SEC("license") = "GPL";12 13struct {14 __uint(type, BPF_MAP_TYPE_HASH);15 __uint(max_entries, 1);16 __type(key, u64);17 __type(value, u64);18} m_hash SEC(".maps");19 20SEC("?raw_tp")21__failure __msg("R8 invalid mem access 'map_value_or_null")22int jeq_infer_not_null_ptr_to_btfid(void *ctx)23{24 struct bpf_map *map = (struct bpf_map *)&m_hash;25 struct bpf_map *inner_map = map->inner_map_meta;26 u64 key = 0, ret = 0, *val;27 28 val = bpf_map_lookup_elem(map, &key);29 /* Do not mark ptr as non-null if one of them is30 * PTR_TO_BTF_ID (R9), reject because of invalid31 * access to map value (R8).32 *33 * Here, we need to inline those insns to access34 * R8 directly, since compiler may use other reg35 * once it figures out val==inner_map.36 */37 asm volatile("r8 = %[val];\n"38 "r9 = %[inner_map];\n"39 "if r8 != r9 goto +1;\n"40 "%[ret] = *(u64 *)(r8 +0);\n"41 : [ret] "+r"(ret)42 : [inner_map] "r"(inner_map), [val] "r"(val)43 : "r8", "r9");44 45 return ret;46}47