High level conclusions

Fuzzers reach 86.45% of cyclomatic complexity.

Fuzzers reach 61.34% of all functions.

Reachability and coverage overview

Functions statically reachable by fuzzers

146/238

Cyclomatic complexity statically reachable by fuzzers

5463/6319

Runtime code coverage of functions

151 / 238

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	Fuzzers runtime hit	Func lines hit %	I Count	BB Count	Cyclomatic complexity	Functions reached	Reached by functions	Accumulated cyclomatic complexity	Undiscovered complexity

Fuzzer: round_trip_frame_uncompressed_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	180	42.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	248	57.9%
All colors	428	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
1447	1447	1 : View List ['LZ4_compress_HC_continue']	1447	1447	LZ4F_compressBlockHC	call site: 00149	/src/lz4/lib/lz4frame.c:876
1406	1406	1 : View List ['LZ4HC_compress_generic_dictCtx']	1406	1406	LZ4HC_compress_generic	call site: 00168	/src/lz4/lib/lz4hc.c:930
870	870	1 : View List ['LZ4_compress_fast_continue']	870	870	LZ4F_compressBlock	call site: 00092	/src/lz4/lib/lz4frame.c:858
354	354	3 : View List ['LZ4_decompress_safe_forceExtDict', 'LZ4_decompress_safe_withPrefix64k', 'LZ4_decompress_safe_withSmallPrefix']	354	354	LZ4_decompress_safe_usingDict	call site: 00376	/src/lz4/lib/lz4.c:2643
20	20	1 : View List ['LZ4F_localSaveDict']	20	20	LZ4F_flush	call site: 00265	/src/lz4/lib/lz4frame.c:1132
14	14	1 : View List ['LZ4_resetStream_fast']	14	19	LZ4F_initStream	call site: 00063	/src/lz4/lib/lz4frame.c:644
2	2	1 : View List ['LZ4F_writeLE64']	2	85	LZ4F_compressBegin_usingCDict	call site: 00073	/src/lz4/lib/lz4frame.c:768
2	2	1 : View List ['LZ4F_readLE64']	2	4	LZ4F_decodeHeader	call site: 00346	/src/lz4/lib/lz4frame.c:1370
2	2	1 : View List ['LZ4F_returnErrorCode']	2	2	LZ4F_getBlockSize	call site: 00025	/src/lz4/lib/lz4frame.c:330
2	2	1 : View List ['LZ4F_returnErrorCode']	2	2	LZ4F_compressEnd	call site: 00323	/src/lz4/lib/lz4frame.c:1179
2	2	1 : View List ['LZ4F_returnErrorCode']	2	2	LZ4F_createDecompressionContext	call site: 00330	/src/lz4/lib/lz4frame.c:1251
0	43	1 : View List ['LZ4F_initStream']	2	132	LZ4F_compressBegin_usingCDict	call site: 00062	/src/lz4/lib/lz4frame.c:745

Runtime coverage analysis

Covered functions

119

Functions that are reachable but not covered

29

Reachable functions

118

Percentage of reachable functions covered

75.42%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/round_trip_frame_uncompressed_fuzzer.c	4
ossfuzz/fuzz_data_producer.c	8
lib/lz4.c	21
lib/lz4frame.c	40
lib/lz4hc.c	20
lib/./lz4.c	6
lib/xxhash.c	10

Fuzzer: decompress_frame_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	26	18.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	2	1.38%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	116	80.5%
All colors	144	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
118	118	1 : View List ['LZ4_decompress_safe_withPrefix64k']	118	118	LZ4_decompress_safe_usingDict	call site: 00096	/src/lz4/lib/lz4.c:2646
0	2	1 : View List ['LZ4F_returnErrorCode']	0	2	LZ4F_getBlockSize	call site: 00032	/src/lz4/lib/lz4frame.c:330
0	2	1 : View List ['LZ4F_returnErrorCode']	0	2	LZ4F_createDecompressionContext	call site: 00011	/src/lz4/lib/lz4frame.c:1251
0	0	None	32	86	LZ4_XXH32_update	call site: 00051	/src/lz4/lib/xxhash.c:519
0	0	None	16	84	LZ4_XXH32	call site: 00092	/src/lz4/lib/xxhash.c:411
0	0	None	0	1535	LZ4F_decompress	call site: 00044	/src/lz4/lib/lz4frame.c:1661
0	0	None	0	1535	LZ4F_decompress	call site: 00047	/src/lz4/lib/lz4frame.c:1704
0	0	None	0	1535	LZ4F_decompress	call site: 00054	/src/lz4/lib/lz4frame.c:1756
0	0	None	0	1535	LZ4F_decompress	call site: 00054	/src/lz4/lib/lz4frame.c:1762
0	0	None	0	1535	LZ4F_decompress	call site: 00062	/src/lz4/lib/lz4frame.c:1799
0	0	None	0	1535	LZ4F_decompress	call site: 00086	/src/lz4/lib/lz4frame.c:1827
0	0	None	0	1535	LZ4F_decompress	call site: 00121	/src/lz4/lib/lz4frame.c:1868

Runtime coverage analysis

Covered functions

52

Functions that are reachable but not covered

6

Reachable functions

47

Percentage of reachable functions covered

87.23%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/decompress_frame_fuzzer.c	2
ossfuzz/fuzz_data_producer.c	5
lib/lz4frame.c	16
lib/xxhash.c	10
lib/lz4.c	9

Fuzzer: decompress_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	21	36.8%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	36	63.1%
All colors	57	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
238	238	2 : View List ['LZ4_decompress_safe_partial_withPrefix64k', 'LZ4_decompress_safe_partial_withSmallPrefix']	238	238	LZ4_decompress_safe_partial_usingDict	call site: 00040	/src/lz4/lib/lz4.c:2660
236	236	2 : View List ['LZ4_decompress_safe_withPrefix64k', 'LZ4_decompress_safe_withSmallPrefix']	236	236	LZ4_decompress_safe_usingDict	call site: 00009	/src/lz4/lib/lz4.c:2645
0	0	None	0	0	LZ4_readLE16	call site: 00013	/src/lz4/lib/lz4.c:426
0	0	None	0	0	FUZZ_dataProducer_retrieve32	call site: 00003	/src/lz4/ossfuzz/fuzz_data_producer.c:23
0	0	None	0	0	FUZZ_getRange_from_uint32	call site: 00005	/src/lz4/ossfuzz/fuzz_data_producer.c:37

Runtime coverage analysis

Covered functions

22

Functions that are reachable but not covered

7

Reachable functions

23

Percentage of reachable functions covered

69.57%

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
ossfuzz/decompress_fuzzer.c	1
ossfuzz/fuzz_data_producer.c	5
lib/lz4.c	14

Fuzzer: round_trip_hc_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	57	47.5%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	63	52.5%
All colors	120	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
1406	1406	1 : View List ['LZ4HC_compress_generic_dictCtx']	1406	1406	LZ4HC_compress_generic	call site: 00027	/src/lz4/lib/lz4hc.c:930
0	12	1 : View List ['LZ4_initStreamHC']	0	15	LZ4_resetStreamHC_fast	call site: 00019	/src/lz4/lib/lz4hc.c:1051
0	0	None	12	276	LZ4HC_compress_optimal	call site: 00075	/src/lz4/lib/lz4hc.c:1476
0	0	None	0	1409	LZ4_compress_HC_extStateHC_fastReset	call site: 00026	/src/lz4/lib/lz4hc.c:958
0	0	None	0	0	LZ4_readLE16	call site: 00109	/src/lz4/lib/lz4.c:426
0	0	None	0	0	LZ4_NbCommonBytes	call site: 00000	/src/lz4/lib/./lz4.c:564
0	0	None	0	0	LZ4_writeLE16	call site: 00048	/src/lz4/lib/./lz4.c:436
0	0	None	0	0	LZ4HC_countPattern	call site: 00000	/src/lz4/lib/lz4hc.c:193
0	0	None	0	0	LZ4HC_compress_optimal	call site: 00073	/src/lz4/lib/lz4hc.c:1390
0	0	None	0	0	LZ4HC_compress_optimal	call site: 00089	/src/lz4/lib/lz4hc.c:1579
0	0	None	0	0	FUZZ_dataProducer_retrieve32	call site: 00004	/src/lz4/ossfuzz/fuzz_data_producer.c:23
0	0	None	0	0	FUZZ_getRange_from_uint32	call site: 00005	/src/lz4/ossfuzz/fuzz_data_producer.c:37

Runtime coverage analysis

Covered functions

51

Functions that are reachable but not covered

8

Reachable functions

42

Percentage of reachable functions covered

80.95%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/round_trip_hc_fuzzer.c	1
ossfuzz/fuzz_data_producer.c	6
lib/lz4.c	6
lib/lz4hc.c	15
lib/./lz4.c	6

Fuzzer: compress_frame_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	202	49.7%
gold	[1:9]	0	0.0%
yellow	[10:29]	1	0.24%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	203	50.0%
All colors	406	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
1447	1447	1 : View List ['LZ4_compress_HC_continue']	1447	1447	LZ4F_compressBlockHC	call site: 00139	/src/lz4/lib/lz4frame.c:876
1406	1406	1 : View List ['LZ4HC_compress_generic_dictCtx']	1406	1406	LZ4HC_compress_generic	call site: 00158	/src/lz4/lib/lz4hc.c:930
870	870	1 : View List ['LZ4_compress_fast_continue']	870	870	LZ4F_compressBlock	call site: 00082	/src/lz4/lib/lz4frame.c:858
354	354	3 : View List ['LZ4_decompress_safe_forceExtDict', 'LZ4_decompress_safe_withPrefix64k', 'LZ4_decompress_safe_withSmallPrefix']	354	354	LZ4_decompress_safe_usingDict	call site: 00356	/src/lz4/lib/lz4.c:2643
20	3332	4 : View List ['LZ4F_localSaveDict', 'LZ4F_selectCompression', 'LZ4F_makeBlock', 'LZ4F_returnErrorCode']	20	3332	LZ4F_flush	call site: 00245	/src/lz4/lib/lz4frame.c:1111
20	20	1 : View List ['LZ4F_localSaveDict']	20	93	LZ4F_compressUpdateImpl	call site: 00268	/src/lz4/lib/lz4frame.c:1023
14	14	1 : View List ['LZ4_resetStream_fast']	14	19	LZ4F_initStream	call site: 00053	/src/lz4/lib/lz4frame.c:644
2	2	1 : View List ['LZ4F_writeLE64']	2	85	LZ4F_compressBegin_usingCDict	call site: 00063	/src/lz4/lib/lz4frame.c:768
2	2	1 : View List ['LZ4F_readLE64']	2	4	LZ4F_decodeHeader	call site: 00326	/src/lz4/lib/lz4frame.c:1370
0	3333	1 : View List ['LZ4F_flush']	40	3704	LZ4F_compressUpdateImpl	call site: 00244	/src/lz4/lib/lz4frame.c:954
0	43	1 : View List ['LZ4F_initStream']	2	132	LZ4F_compressBegin_usingCDict	call site: 00052	/src/lz4/lib/lz4frame.c:745
0	12	1 : View List ['LZ4_initStreamHC']	0	15	LZ4_resetStreamHC_fast	call site: 00057	/src/lz4/lib/lz4hc.c:1051

Runtime coverage analysis

Covered functions

114

Functions that are reachable but not covered

29

Reachable functions

114

Percentage of reachable functions covered

74.56%

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
ossfuzz/compress_frame_fuzzer.c	1
ossfuzz/fuzz_data_producer.c	8
lib/lz4frame.c	35
lib/lz4.c	21
lib/lz4hc.c	20
lib/./lz4.c	6
lib/xxhash.c	10
ossfuzz/lz4_helpers.c	1

Fuzzer: round_trip_frame_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	169	40.8%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	1	0.24%
lawngreen	50+	244	58.9%
All colors	414	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
1406	1406	1 : View List ['LZ4HC_compress_generic_dictCtx']	1406	1406	LZ4HC_compress_generic	call site: 00158	/src/lz4/lib/lz4hc.c:930
118	118	1 : View List ['LZ4_decompress_safe_withSmallPrefix']	118	118	LZ4_decompress_safe_usingDict	call site: 00365	/src/lz4/lib/lz4.c:2646
29	29	1 : View List ['LZ4_loadDictHC']	40	1449	LZ4_compressHC_continue_generic	call site: 00144	/src/lz4/lib/lz4hc.c:1137
24	3332	4 : View List ['LZ4F_localSaveDict', 'LZ4F_selectCompression', 'LZ4F_makeBlock', 'LZ4F_returnErrorCode']	24	3332	LZ4F_flush	call site: 00245	/src/lz4/lib/lz4frame.c:1111
20	20	1 : View List ['LZ4F_localSaveDict']	20	93	LZ4F_compressUpdateImpl	call site: 00268	/src/lz4/lib/lz4frame.c:1023
11	11	1 : View List ['LZ4HC_setExternalDict']	11	1420	LZ4_compressHC_continue_generic	call site: 00147	/src/lz4/lib/lz4hc.c:1144
2	8	3 : View List ['LZ4F_free', 'LZ4F_returnErrorCode', 'LZ4F_malloc']	4	142	LZ4F_compressBegin_usingCDict	call site: 00048	/src/lz4/lib/lz4frame.c:732
2	2	1 : View List ['LZ4F_writeLE64']	2	85	LZ4F_compressBegin_usingCDict	call site: 00063	/src/lz4/lib/lz4frame.c:768
2	2	1 : View List ['LZ4F_readLE64']	2	4	LZ4F_decodeHeader	call site: 00334	/src/lz4/lib/lz4frame.c:1370
2	2	1 : View List ['LZ4F_returnErrorCode']	2	2	LZ4F_getBlockSize	call site: 00018	/src/lz4/lib/lz4frame.c:330
2	2	1 : View List ['LZ4F_returnErrorCode']	2	2	LZ4F_compressEnd	call site: 00306	/src/lz4/lib/lz4frame.c:1179
2	2	1 : View List ['LZ4F_returnErrorCode']	2	2	LZ4F_createDecompressionContext	call site: 00317	/src/lz4/lib/lz4frame.c:1251

Runtime coverage analysis

Covered functions

124

Functions that are reachable but not covered

20

Reachable functions

114

Percentage of reachable functions covered

82.46%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/round_trip_frame_fuzzer.c	1
ossfuzz/fuzz_data_producer.c	8
lib/lz4.c	21
lib/lz4frame.c	38
lib/lz4hc.c	20
lib/./lz4.c	6
lib/xxhash.c	10
ossfuzz/lz4_helpers.c	1

Fuzzer: round_trip_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	47	41.9%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	65	58.0%
All colors	112	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
238	238	2 : View List ['LZ4_decompress_safe_partial_withPrefix64k', 'LZ4_decompress_safe_partial_withSmallPrefix']	238	238	LZ4_decompress_safe_partial_usingDict	call site: 00076	/src/lz4/lib/lz4.c:2660
0	0	None	16	384	LZ4_compress_fast_extState	call site: 00048	/src/lz4/lib/lz4.c:1362
0	0	None	0	0	LZ4_writeLE16	call site: 00000	/src/lz4/lib/./lz4.c:436
0	0	None	0	0	LZ4_NbCommonBytes	call site: 00000	/src/lz4/lib/./lz4.c:564
0	0	None	0	0	LZ4_readLE16	call site: 00057	/src/lz4/lib/lz4.c:426
0	0	None	0	0	FUZZ_dataProducer_retrieve32	call site: 00003	/src/lz4/ossfuzz/fuzz_data_producer.c:23
0	0	None	0	0	FUZZ_getRange_from_uint32	call site: 00005	/src/lz4/ossfuzz/fuzz_data_producer.c:37

Runtime coverage analysis

Covered functions

40

Functions that are reachable but not covered

7

Reachable functions

33

Percentage of reachable functions covered

78.79%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/round_trip_fuzzer.c	1
ossfuzz/fuzz_data_producer.c	5
lib/lz4.c	18

Fuzzer: compress_hc_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	54	41.5%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	76	58.4%
All colors	130	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
1406	1406	1 : View List ['LZ4HC_compress_generic_dictCtx']	1406	1406	LZ4HC_compress_generic	call site: 00027	/src/lz4/lib/lz4hc.c:930
0	12	1 : View List ['LZ4_initStreamHC']	0	15	LZ4_resetStreamHC_fast	call site: 00019	/src/lz4/lib/lz4hc.c:1051
0	0	None	12	276	LZ4HC_compress_optimal	call site: 00075	/src/lz4/lib/lz4hc.c:1476
0	0	None	0	1409	LZ4_compress_HC_extStateHC_fastReset	call site: 00026	/src/lz4/lib/lz4hc.c:958
0	0	None	0	0	LZ4_readLE16	call site: 00108	/src/lz4/lib/lz4.c:426
0	0	None	0	0	LZ4_NbCommonBytes	call site: 00000	/src/lz4/lib/./lz4.c:564
0	0	None	0	0	LZ4_writeLE16	call site: 00048	/src/lz4/lib/./lz4.c:436
0	0	None	0	0	LZ4HC_countPattern	call site: 00000	/src/lz4/lib/lz4hc.c:193
0	0	None	0	0	FUZZ_getRange_from_uint32	call site: 00006	/src/lz4/ossfuzz/fuzz_data_producer.c:37

Runtime coverage analysis

Covered functions

52

Functions that are reachable but not covered

8

Reachable functions

43

Percentage of reachable functions covered

81.4%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/compress_hc_fuzzer.c	1
ossfuzz/fuzz_data_producer.c	5
lib/lz4hc.c	17
lib/./lz4.c	6
lib/lz4.c	6

Fuzzer: compress_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	39	50.0%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	39	50.0%
All colors	78	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
0	0	None	8	192	LZ4_compress_fast_extState	call site: 00047	/src/lz4/lib/lz4.c:1363
0	0	None	0	0	LZ4_writeLE16	call site: 00000	/src/lz4/lib/./lz4.c:436
0	0	None	0	0	LZ4_NbCommonBytes	call site: 00000	/src/lz4/lib/./lz4.c:564
0	0	None	0	0	LZ4_readLE16	call site: 00055	/src/lz4/lib/lz4.c:426
0	0	None	0	0	FUZZ_dataProducer_retrieve32	call site: 00003	/src/lz4/ossfuzz/fuzz_data_producer.c:23
0	0	None	0	0	FUZZ_getRange_from_uint32	call site: 00006	/src/lz4/ossfuzz/fuzz_data_producer.c:37

Runtime coverage analysis

Covered functions

39

Functions that are reachable but not covered

5

Reachable functions

30

Percentage of reachable functions covered

83.33%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/compress_fuzzer.c	1
ossfuzz/fuzz_data_producer.c	5
lib/lz4.c	15

Fuzzer: round_trip_stream_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

Call tree overview bitmap:

The distribution of callsites in terms of coloring is

Color	Runtime hitcount	Callsite count	Percentage
red	0	6	12.2%
gold	[1:9]	0	0.0%
yellow	[10:29]	0	0.0%
greenyellow	[30:49]	0	0.0%
lawngreen	50+	43	87.7%
All colors	49	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
0	29	1 : View List ['LZ4_loadDictHC']	0	1449	LZ4_compressHC_continue_generic	call site: 00000	/src/lz4/lib/lz4hc.c:1137
0	12	1 : View List ['LZ4_initStreamHC']	0	15	LZ4_resetStreamHC_fast	call site: 00031	/src/lz4/lib/lz4hc.c:1051
0	0	None	24	84	LZ4_XXH32	call site: 00008	/src/lz4/lib/xxhash.c:411
0	0	None	0	1442	LZ4_compress_HC_continue	call site: 00000	/src/lz4/lib/lz4hc.c:1167
0	0	None	0	276	LZ4HC_compress_optimal	call site: 00000	/src/lz4/lib/lz4hc.c:1476
0	0	None	0	0	LZ4_attach_dictionary	call site: 00000	/src/lz4/lib/lz4.c:1610
0	0	None	0	0	LZ4_writeLE16	call site: 00000	/src/lz4/lib/./lz4.c:436
0	0	None	0	0	LZ4_NbCommonBytes	call site: 00000	/src/lz4/lib/./lz4.c:564
0	0	None	0	0	LZ4_readLE16	call site: 00000	/src/lz4/lib/lz4.c:426
0	0	None	0	0	LZ4HC_countPattern	call site: 00000	/src/lz4/lib/lz4hc.c:193
0	0	None	0	0	LZ4HC_compress_optimal	call site: 00000	/src/lz4/lib/lz4hc.c:1390
0	0	None	0	0	LZ4HC_compress_optimal	call site: 00000	/src/lz4/lib/lz4hc.c:1579

Runtime coverage analysis

Covered functions

103

Functions that are reachable but not covered

7

Reachable functions

38

Percentage of reachable functions covered

81.58%

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.

Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.

Function name	source code lines	source lines hit	percentage hit

Files reached

filename	functions hit
ossfuzz/round_trip_stream_fuzzer.c	7
ossfuzz/./fuzz_helpers.h	3
lib/xxhash.c	4
lib/lz4.c	9
lib/lz4hc.c	6
lib/./lz4.c	1

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
LZ4_compress_forceExtDict	/src/lz4/lib/lz4.c	4	['union.LZ4_stream_u *', 'char *', 'char *', 'int ']	1	0	9175	1109	278	11	0	306	278
state_loadDictRoundTrip	/src/lz4/ossfuzz/round_trip_stream_fuzzer.c	1	['struct.state_t *']	4	0	42	3	2	32	0	1455	139
LZ4_XXH64	/src/lz4/lib/xxhash.c	3	['char *', 'size_t ', 'size_t ']	1	0	820	90	31	10	0	133	125
LZ4_XXH64_update	/src/lz4/lib/xxhash.c	3	['struct.XXH64_state_s *', 'char *', 'size_t ']	0	0	1666	184	63	5	0	73	63
LZ4_decompress_fast_continue	/src/lz4/lib/lz4.c	4	['union.LZ4_streamDecode_u *', 'char *', 'char *', 'int ']	1	0	543	59	19	7	0	58	49

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

Functions statically reachable by fuzzers

168/238

Cyclomatic complexity statically reachable by fuzzers

6117 / 6319

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	Fuzzers runtime hit	Func lines hit %	I Count	BB Count	Cyclomatic complexity	Functions reached	Reached by functions	Accumulated cyclomatic complexity	Undiscovered complexity

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

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/lz4/ossfuzz/round_trip_stream_fuzzer.c	['round_trip_stream_fuzzer']	['round_trip_stream_fuzzer']
/src/lz4/ossfuzz/compress_frame_fuzzer.c	['compress_frame_fuzzer']	['compress_frame_fuzzer']
/src/lz4/lib/lz4frame.c	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer']	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer']
/src/lz4/ossfuzz/decompress_fuzzer.c	['decompress_fuzzer']	['decompress_fuzzer']
/src/lz4/ossfuzz/./fuzz_helpers.h	['round_trip_stream_fuzzer']	[]
/src/lz4/lib/lz4hc.c	['round_trip_frame_uncompressed_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'compress_hc_fuzzer', 'round_trip_stream_fuzzer']	['round_trip_frame_uncompressed_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'compress_hc_fuzzer', 'round_trip_stream_fuzzer']
/src/lz4/ossfuzz/decompress_frame_fuzzer.c	['decompress_frame_fuzzer']	['decompress_frame_fuzzer']
/src/lz4/ossfuzz/fuzz_data_producer.c	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'decompress_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'round_trip_fuzzer', 'compress_hc_fuzzer', 'compress_fuzzer']	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'decompress_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'round_trip_fuzzer', 'compress_hc_fuzzer', 'compress_fuzzer']
/src/lz4/ossfuzz/round_trip_frame_uncompressed_fuzzer.c	['round_trip_frame_uncompressed_fuzzer']	['round_trip_frame_uncompressed_fuzzer']
/src/lz4/ossfuzz/round_trip_frame_fuzzer.c	['round_trip_frame_fuzzer']	['round_trip_frame_fuzzer']
/src/lz4/lib/./lz4.c	['round_trip_frame_uncompressed_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'compress_hc_fuzzer', 'round_trip_stream_fuzzer']	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'decompress_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'round_trip_fuzzer', 'compress_hc_fuzzer', 'compress_fuzzer', 'round_trip_stream_fuzzer']
/src/lz4/ossfuzz/round_trip_fuzzer.c	['round_trip_fuzzer']	['round_trip_fuzzer']
/src/lz4/lib/lz4.c	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'decompress_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'round_trip_fuzzer', 'compress_hc_fuzzer', 'compress_fuzzer', 'round_trip_stream_fuzzer']	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'decompress_fuzzer', 'round_trip_hc_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'round_trip_fuzzer', 'compress_hc_fuzzer', 'compress_fuzzer', 'round_trip_stream_fuzzer']
/src/lz4/ossfuzz/compress_hc_fuzzer.c	['compress_hc_fuzzer']	['compress_hc_fuzzer']
/src/lz4/ossfuzz/compress_fuzzer.c	['compress_fuzzer']	['compress_fuzzer']
/src/lz4/lib/xxhash.c	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'round_trip_stream_fuzzer']	['round_trip_frame_uncompressed_fuzzer', 'decompress_frame_fuzzer', 'compress_frame_fuzzer', 'round_trip_frame_fuzzer', 'round_trip_stream_fuzzer']
/src/lz4/ossfuzz/round_trip_hc_fuzzer.c	['round_trip_hc_fuzzer']	['round_trip_hc_fuzzer']
/src/lz4/ossfuzz/lz4_helpers.c	['compress_frame_fuzzer', 'round_trip_frame_fuzzer']	['compress_frame_fuzzer', 'round_trip_frame_fuzzer']

Directories in report

Directory
/src/lz4/ossfuzz/./
/src/lz4/lib/./
/src/lz4/lib/
/src/lz4/ossfuzz/

This section shows a chosen list of functions / methods calls and their relative coverage information. By static analysis of the target project code, all of these function call and their caller information, including the source file or class and line number that initiate the call are captured. Column 1 is the function name of that selected functions or methods. Column 2 of each row indicate if the target function covered by any fuzzer calltree information. Column 3 lists all fuzzers (or no fuzzers at all) that have coered that particular function call dynamically. Column 4 shows list of parent function for the specific function call, while column 5 shows possible blocker functions that make the fuzzers fail to reach the specific functions. Both column 4 and 5 will only show information if none of the fuzzers cover the target function calls.

Function in each files in report

Target sink	Callsite location	Reached by fuzzer	Function call path	Covered by fuzzer	Possible branch blockers