Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues
Project coverage
Per-fuzzer coverage

Table of contents

Project overview: libbpf
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: bpf-object-fuzzer
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
fuzz/bpf-object-fuzzer.c
Dictionary
Fuzzer function priority
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2025-06-22

Project overview: libbpf

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
28.0%
305 / 1090
Cyclomatic complexity statically reachable by fuzzers
30.0%
2118 / 7163
Runtime code coverage of functions
25.0%
276 / 1090

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
bpf-object-fuzzer fuzz/bpf-object-fuzzer.c 352 825 13 39 5482 2213 bpf-object-fuzzer.c

Project functions overview

The following table shows data about each function in the project. The functions included in this table correspond to all functions that exist in the executables of the fuzzers. As such, there may be functions that are from third-party libraries.

For further technical details on the meaning of columns in the below table, please see the Glossary .

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzzer details

Fuzzer: bpf-object-fuzzer

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 413 29.3%
gold [1:9] 83 5.89%
yellow [10:29] 53 3.76%
greenyellow [30:49] 24 1.70%
lawngreen 50+ 834 59.2%
All colors 1407 100

Fuzz blockers

The followings are the branches where fuzzer fails to bypass.

Unique non-covered Complexity Unique Reachable Complexities Unique Reachable Functions All non-covered Complexity All Reachable Complexity Function Name Function Callsite Blocked Branch
260 264 4 :

['elf_begin', 'open64', 'libbpf_errstr', '__errno_location']

260 624 bpf_object__elf_init call site: 00054 /src/libbpf/src/libbpf.c:1556
178 178 1 :

['elf32_getchdr']

178 178 gelf_getchdr call site: 00341 /src/libbpf/elfutils/libelf/gelf_getchdr.c:50
133 133 1 :

['btf__find_str']

133 292 btf__add_str call site: 00761 /src/libbpf/src/btf.c:1815
61 61 1 :

['__elf32_getshdr_rdlock']

61 457 elf_strptr call site: 00333 /src/libbpf/elfutils/libelf/elf_strptr.c:121
60 60 1 :

['__elf32_getshdr_wrlock']

60 107 __libelf_set_rawdata_wrlock call site: 00227 /src/libbpf/elfutils/libelf/elf_getdata.c:223
22 1342 16 :

['btf_array', 'get_map_field_long', 'btf__name_by_offset', 'bpf_map_type__is_map_in_map', 'btf_kind_str', 'strcmp', 'btf_is_array', 'btf_is_func_proto', 'btf__type_by_id', 'btf_is_ptr', 'btf_is_struct', 'btf__resolve_size', 'skip_mods_and_typedefs', 'get_map_field_int', 'libbpf_print', 'parse_btf_map_def']

22 1342 parse_btf_map_def call site: 01081 /src/libbpf/src/libbpf.c:2719
22 1217 15 :

['btf_array', 'get_map_field_long', 'btf__name_by_offset', 'bpf_map_type__is_map_in_map', 'btf_kind_str', 'strcmp', 'btf_is_array', 'btf_is_func_proto', 'btf__type_by_id', 'btf_is_ptr', 'btf_is_struct', 'btf__resolve_size', 'skip_mods_and_typedefs', 'get_map_field_int', 'parse_btf_map_def']

22 1342 parse_btf_map_def call site: 01081 /src/libbpf/src/libbpf.c:2747
8 13 4 :

['close', 'libbpf_print', '__errno_location', 'dup_good_fd.2351']

8 13 ensure_good_fd call site: 00987 /src/libbpf/src/./libbpf_internal.h:652
6 6 3 :

['__isoc99_fscanf', 'fopen64', 'fclose']

6 6 get_ubuntu_kernel_version call site: 00039 /src/libbpf/src/libbpf_probes.c:38
4 62 5 :

['fill_map_from_def', 'calloc', 'create_placeholder_fd', 'malloc', 'strlen']

4 106 bpf_object__init_user_btf_map call site: 01134 /src/libbpf/src/libbpf.c:2937
4 4 2 :

['strchr', '__xpg_basename']

4 39 bpf_object__new call site: 00032 /src/libbpf/src/libbpf.c:1499
4 4 2 :

['pread', '__errno_location']

4 4 pread_retry call site: 00071 /src/libbpf/elfutils/libelf/../lib/system.h:193

Runtime coverage analysis

Covered functions
277
Functions that are reachable but not covered
82
Reachable functions
352
Percentage of reachable functions covered
76.7%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
fuzz/bpf-object-fuzzer.c 2
src/libbpf.c 113
src/./libbpf_internal.h 19
src/../include/linux/err.h 4
elfutils/libelf/elf_version.c 1
elfutils/libelf/elf_error.c 2
src/libbpf_probes.c 3
elfutils/libelf/elf_memory.c 1
elfutils/libelf/elf_begin.c 12
elfutils/libelf/./common.h 2
/usr/include/x86_64-linux-gnu/bits/byteswap.h 3
elfutils/libelf/../lib/system.h 1
src/str_error.c 1
elfutils/libelf/elf_kind.c 1
elfutils/libelf/gelf_getclass.c 1
elfutils/libelf/./elf32_getehdr.c 2
elfutils/libelf/elf_getshdrstrndx.c 1
elfutils/libelf/elf_getscn.c 1
elfutils/libelf/elf_rawdata.c 1
elfutils/libelf/elf_getdata.c 7
elfutils/libelf/elf32_getshdr.c 5
elfutils/libelf/elf_getshdrnum.c 2
elfutils/libelf/./elf32_getshdr.c 5
elfutils/libelf/gelf_getehdr.c 1
elfutils/libelf/elf_end.c 1
elfutils/libelf/elf_nextscn.c 1
elfutils/libelf/elf_ndxscn.c 1
elfutils/libelf/elf_strptr.c 3
elfutils/libelf/elf_compress.c 3
elfutils/libelf/gelf_getchdr.c 1
elfutils/libelf/elf32_getchdr.c 1
elfutils/libelf/./elf32_getchdr.c 1
src/btf.c 53
src/./btf.h 29
src/strset.c 9
src/hashmap.c 10
src/./hashmap.h 2
src/usdt.c 1
src/gen_loader.c 1

Analyses and suggestions

Optimal target analysis

Remaining optimal interesting functions

The following table shows a list of functions that are optimal targets. Optimal targets are identified by finding the functions that in combination, yield a high code coverage.

Func name Functions filename Arg count Args Function depth hitcount instr count bb count cyclomatic complexity Reachable functions Incoming references total cyclomatic complexity Unreached complexity
bpf_object__load_skeleton /src/libbpf/src/libbpf.c 1 ['N/A'] 19 0 103 14 5 522 0 3338 2013
attach_usdt /src/libbpf/src/libbpf.c 3 ['N/A', 'size_t', 'N/A'] 14 0 93 11 4 231 0 1659 791
btf__dedup /src/libbpf/src/btf.c 2 ['N/A', 'N/A'] 11 0 213 48 14 117 0 598 352
btf__distill_base /src/libbpf/src/btf.c 3 ['N/A', 'N/A', 'N/A'] 10 0 310 45 18 77 0 347 92
elf_compress /src/libbpf/elfutils/libelf/elf_compress.c 3 ['N/A', 'int', 'int'] 10 0 575 65 27 45 0 332 92
attach_kprobe_multi /src/libbpf/src/libbpf.c 3 ['N/A', 'size_t', 'N/A'] 7 0 125 16 6 54 0 324 86
perf_buffer__new_raw /src/libbpf/src/libbpf.c 6 ['int', 'size_t', 'N/A', 'N/A', 'N/A', 'N/A'] 6 0 165 29 11 40 0 155 64
libbpf_prepare_prog_load /src/libbpf/src/libbpf.c 3 ['N/A', 'N/A', 'size_t'] 11 0 213 33 13 93 0 400 61
bpf_object__pin /src/libbpf/src/libbpf.c 2 ['N/A', 'N/A'] 7 0 59 8 4 39 0 182 56
attach_ksyscall /src/libbpf/src/libbpf.c 3 ['N/A', 'size_t', 'N/A'] 8 0 115 15 6 60 0 322 52

Implementing fuzzers that target the above functions will improve reachability such that it becomes:

Functions statically reachable by fuzzers
70.0%
761 / 1090
Cyclomatic complexity statically reachable by fuzzers
80.0%
5707 / 7163

All functions overview

If you implement fuzzers for these functions, the status of all functions in the project will be:

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzz engine guidance

This sections provides heuristics that can be used as input to a fuzz engine when running a given fuzz target. The current focus is on providing input that is usable by libFuzzer.

fuzz/bpf-object-fuzzer.c

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name 

-focus_function=['libbpf_errstr', 'find_prog_by_sec_insn', 'bpf_object_init_progs', 'load_shdr_wrlock', '__libelf_decompress_elf', 'get_debian_kernel_version', 'bpf_object__elf_init', 'bpf_map__set_pin_path', '__libelf_set_rawdata_wrlock', 'btf__add_var']

Runtime coverage analysis

This section shows analysis of runtime coverage data.

For futher technical details on how this section is generated, please see the Glossary .

Complex functions with low coverage

Func name Function total lines Lines covered at runtime percentage covered Reached by fuzzers
load_shdr_wrlock 133 68 51.12% ['bpf-object-fuzzer']
__elf_getdata_rdlock 50 22 44.0% ['bpf-object-fuzzer']
elf_getscn 63 30 47.61% ['bpf-object-fuzzer']
elf_getshdrstrndx 142 62 43.66% ['bpf-object-fuzzer']
__gelf_getehdr_rdlock 39 12 30.76% ['bpf-object-fuzzer']
bpf_object_open 70 19 27.14% ['bpf-object-fuzzer']
libbpf_errstr 63 12 19.04% ['bpf-object-fuzzer']

Files and Directories in report

This section shows which files and directories are considered in this report. The main reason for showing this is fuzz introspector may include more code in the reasoning than is desired. This section helps identify if too many files/directories are included, e.g. third party code, which may be irrelevant for the threat model. In the event too much is included, fuzz introspector supports a configuration file that can exclude data from the report. See the following link for more information on how to create a config file: link

Files in report

Source file Reached by Covered by
[] []
/src/libbpf/src/str_error.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/./libbpf_internal.h ['bpf-object-fuzzer'] []
/src/libbpf/src/bpf.c [] []
/src/libbpf/elfutils/libelf/gelf_getversym.c [] []
/src/libbpf/src/elf.c [] []
/src/libbpf/elfutils/libelf/./gnuhash_xlate.h [] []
/src/libbpf/elfutils/libelf/./chdr_xlate.h [] []
/src/libbpf/elfutils/libelf/gelf_getverdef.c [] []
/src/libbpf/src/../include/linux/ring_buffer.h [] []
/src/libbpf/elfutils/libelf/elf_strptr.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_getdata.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_begin.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/gen_loader.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_end.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf32_xlatetof.c [] []
/src/libbpf/elfutils/libelf/elf32_getchdr.c ['bpf-object-fuzzer'] []
/src/libbpf/fuzz/bpf-object-fuzzer.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_getscn.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/gelf_getnote.c [] []
/src/libbpf/src/features.c [] []
/src/libbpf/src/btf_relocate.c [] []
/src/libbpf/elfutils/libelf/./version_xlate.h [] []
/src/libbpf/elfutils/libelf/elf_version.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_kind.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/zip.c [] []
/src/libbpf/src/libbpf_probes.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_getshdrstrndx.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/usr/include/x86_64-linux-gnu/bits/byteswap.h ['bpf-object-fuzzer'] []
/src/libbpf/src/btf_iter.c [] []
/src/libbpf/elfutils/libelf/./gelf_xlate.h [] []
/src/libbpf/elfutils/libelf/elf_compress.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/./note_xlate.h [] []
/src/libbpf/elfutils/libelf/./elf32_getshdr.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/hashmap.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/./elf32_getphdr.c [] []
/src/libbpf/elfutils/libelf/gelf_getphdr.c [] []
/src/libbpf/elfutils/libelf/../lib/system.h ['bpf-object-fuzzer'] []
/src/libbpf/elfutils/libelf/elf_nextscn.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/relo_core.c [] []
/src/libbpf/src/./btf.h ['bpf-object-fuzzer'] []
/src/libbpf/src/../include/linux/err.h ['bpf-object-fuzzer'] []
/src/libbpf/elfutils/libelf/elf_error.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/./hashmap.h ['bpf-object-fuzzer'] []
/src/libbpf/elfutils/libelf/./elf32_getehdr.c ['bpf-object-fuzzer'] []
/src/libbpf/elfutils/libelf/elf32_getshdr.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/gelf_getverdaux.c [] []
/src/libbpf/elfutils/libelf/elf_getshdrnum.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_ndxscn.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_rawdata.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/gelf_getshdr.c [] []
/src/libbpf/elfutils/libelf/gelf_fsize.c [] []
/src/libbpf/elfutils/libelf/gelf_getsym.c [] []
/src/libbpf/elfutils/libelf/elf_getphdrnum.c [] []
/src/libbpf/elfutils/libelf/./elf32_xlatetof.c [] []
/src/libbpf/elfutils/libelf/gelf_getehdr.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/gelf_getclass.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/gelf_xlatetof.c [] []
/src/libbpf/elfutils/libelf/elf32_getphdr.c [] []
/src/libbpf/elfutils/libelf/gelf_getchdr.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/btf.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/./elf32_getchdr.c ['bpf-object-fuzzer'] []
/src/libbpf/src/libbpf.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/src/usdt.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/./common.h ['bpf-object-fuzzer'] []
/src/libbpf/elfutils/libelf/gelf_xlate.c [] []
/src/libbpf/src/strset.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']
/src/libbpf/elfutils/libelf/elf_memory.c ['bpf-object-fuzzer'] ['bpf-object-fuzzer']

Directories in report

Directory
/src/libbpf/elfutils/libelf/./
/src/libbpf/src/
/src/libbpf/src/../include/linux/
/src/libbpf/elfutils/libelf/../lib/
/usr/include/x86_64-linux-gnu/bits/
/src/libbpf/src/./
/src/libbpf/elfutils/libelf/
/src/libbpf/fuzz/

Metadata section

This sections shows the raw data that is used to produce this report. This is mainly used for further processing and developer debugging.

Fuzzer Calltree file Program data file Coverage file
bpf-object-fuzzer fuzzerLogFile-0-P5kZrDIUyH.data fuzzerLogFile-0-P5kZrDIUyH.data.yaml bpf-object-fuzzer.covreport