Fuzzing logs

[xpe]

Here are some fuzz logs showing how ft (feature count) increases slowly:

% cargo fuzz run fuzz_methods
...
#558	INITED cov: 525 ft: 2795 corp: 332/84Kb exec/s: 0 rss: 77Mb
#8069	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 3830 exec/s: 0 rss: 144Mb L: 82/3753 MS: 1 EraseBytes-
#10245	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 3841 exec/s: 0 rss: 179Mb L: 76/3753 MS: 1 EraseBytes-
#16707	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 3896 exec/s: 0 rss: 256Mb L: 969/3753 MS: 2 ChangeBit-EraseBytes-
#39204	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 4096 exec/s: 39204 rss: 265Mb L: 46/3753 MS: 1 EraseBytes-
#60935	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 4096 exec/s: 60935 rss: 273Mb L: 2424/3753 MS: 1 EraseBytes-
...
#244010	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 4096 exec/s: 40668 rss: 297Mb L: 1712/3753 MS: 1 EraseBytes-
#262144	pulse  cov: 525 ft: 2795 corp: 332/84Kb lim: 4096 exec/s: 37449 rss: 314Mb
#286445	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 4096 exec/s: 35805 rss: 318Mb L: 2416/3753 MS: 3 ShuffleBytes-ChangeBit-EraseBytes-
#305917	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 4096 exec/s: 38239 rss: 319Mb L: 275/3753 MS: 2 ChangeByte-EraseBytes-
#324285	REDUCE cov: 525 ft: 2795 corp: 332/84Kb lim: 4096 exec/s: 36031 rss: 319Mb L: 1787/3753 MS: 3 ChangeASCIIInt-ChangeBinInt-EraseBytes-
...
#35952954	REDUCE cov: 525 ft: 2796 corp: 333/80Kb lim: 4096 exec/s: 77652 rss: 371Mb L: 242/3747 MS: 1 CopyPart-
...
#38117522	NEW    cov: 525 ft: 2799 corp: 334/82Kb lim: 4096 exec/s: 77160 rss: 441Mb L: 2130/3747 MS: 2 ChangeBit-CrossOver-
...
#38163805	REDUCE cov: 525 ft: 2800 corp: 335/84Kb lim: 4096 exec/s: 77098 rss: 441Mb L: 2376/3747 MS: 2 CrossOver-CopyPart-
...
#49419178	REDUCE cov: 525 ft: 2801 corp: 336/81Kb lim: 4096 exec/s: 72462 rss: 458Mb L: 440/3682 MS: 1 CopyPart-
...
#78099569	REDUCE cov: 525 ft: 2802 corp: 337/80Kb lim: 4096 exec/s: 69114 rss: 489Mb L: 848/3516 MS: 2 ChangeBit-CopyPart-
...
#99596572	NEW    cov: 525 ft: 2811 corp: 338/80Kb lim: 4096 exec/s: 67984 rss: 540Mb L: 871/3495 MS: 2 CopyPart-CopyPart-
...
#101440107	REDUCE cov: 525 ft: 2814 corp: 339/81Kb lim: 4096 exec/s: 67989 rss: 540Mb L: 1651/3493 MS: 1 CrossOver-
...
#192880009	REDUCE cov: 525 ft: 2815 corp: 340/77Kb lim: 4096 exec/s: 67511 rss: 545Mb L: 105/3286 MS: 3 CrossOver-CrossOver-CopyPart-
...
#209534672	REDUCE cov: 525 ft: 2816 corp: 341/76Kb lim: 4096 exec/s: 58990 rss: 545Mb L: 141/3280 MS: 1 CrossOver-
#209541373	NEW    cov: 525 ft: 2817 corp: 342/77Kb lim: 4096 exec/s: 58992 rss: 545Mb L: 181/3280 MS: 1 CopyPart-
...
#209547401	REDUCE cov: 525 ft: 2818 corp: 343/77Kb lim: 4096 exec/s: 58994 rss: 545Mb L: 315/3280 MS: 1 CopyPart-
...
#209983764	REDUCE cov: 525 ft: 2819 corp: 344/77Kb lim: 4096 exec/s: 59033 rss: 545Mb L: 440/3280 MS: 2 ChangeBinInt-CopyPart-
...
#210498118	REDUCE cov: 525 ft: 2820 corp: 345/78Kb lim: 4096 exec/s: 59062 rss: 545Mb L: 876/3280 MS: 5 CopyPart-InsertByte-ChangeByte-ChangeBinInt-CopyPart-
...
#211504970	REDUCE cov: 525 ft: 2821 corp: 346/78Kb lim: 4096 exec/s: 58751 rss: 549Mb L: 357/3280 MS: 1 CrossOver-
...
#211511318	REDUCE cov: 525 ft: 2822 corp: 347/78Kb lim: 4096 exec/s: 58736 rss: 549Mb L: 461/3280 MS: 2 ChangeBit-CrossOver-
...
#213874416	REDUCE cov: 525 ft: 2823 corp: 348/79Kb lim: 4096 exec/s: 58821 rss: 549Mb L: 733/3276 MS: 3 CopyPart-ChangeBit-CopyPart-
...
#219358847	REDUCE cov: 525 ft: 2824 corp: 349/80Kb lim: 4096 exec/s: 58433 rss: 620Mb L: 1642/3276 MS: 2 CMP-CrossOver- DE: "\007\000\000\000"-
...
#219366447	REDUCE cov: 525 ft: 2827 corp: 350/79Kb lim: 4096 exec/s: 58404 rss: 723Mb L: 630/3276 MS: 2 ChangeBinInt-CopyPart-
...
#219384285	REDUCE cov: 525 ft: 2828 corp: 351/80Kb lim: 4096 exec/s: 58284 rss: 750Mb L: 1015/3276 MS: 1 CopyPart-
...
#219389558	REDUCE cov: 525 ft: 2831 corp: 352/81Kb lim: 4096 exec/s: 58208 rss: 750Mb L: 1006/3276 MS: 2 ChangeBinInt-CopyPart-
...
#219389575	NEW    cov: 525 ft: 2837 corp: 353/82Kb lim: 4096 exec/s: 58208 rss: 750Mb L: 1595/3276 MS: 2 ChangeBit-CopyPart-
...
#219401100	NEW    cov: 525 ft: 2840 corp: 355/88Kb lim: 4096 exec/s: 57676 rss: 750Mb L: 2870/3276 MS: 1 EraseBytes-
...
#219401608	NEW    cov: 525 ft: 2844 corp: 356/91Kb lim: 4096 exec/s: 57615 rss: 750Mb L: 2906/3276 MS: 1 CopyPart-
...
#219433828	REDUCE cov: 525 ft: 2845 corp: 357/91Kb lim: 4096 exec/s: 54221 rss: 750Mb L: 2627/3276 MS: 2 InsertRepeatedBytes-CopyPart-
...
#219481174	REDUCE cov: 525 ft: 2854 corp: 358/94Kb lim: 4096 exec/s: 49916 rss: 750Mb L: 4073/4073 MS: 1 CopyPart-
...
#219509613	NEW    cov: 525 ft: 2855 corp: 359/97Kb lim: 4096 exec/s: 47165 rss: 750Mb L: 4073/4073 MS: 1 CrossOver-
...
#219776078	REDUCE cov: 525 ft: 2856 corp: 360/97Kb lim: 4096 exec/s: 28990 rss: 750Mb L: 4051/4051 MS: 1 CopyPart-
...
#220007939	REDUCE cov: 525 ft: 2860 corp: 361/100Kb lim: 4096 exec/s: 19481 rss: 750Mb L: 3812/4030 MS: 3 ChangeBinInt-ChangeBinInt-CrossOver-
...
#222339797	REDUCE cov: 525 ft: 2860 corp: 361/94Kb lim: 4096 exec/s: 3379 rss: 757Mb L: 3237/3550 MS: 1 EraseBytes-

[xpe]

The output details are explained in the "output" section of this libFuzzer documentation page; e.g.

cov:
Total number of code blocks or edges covered by executing the current corpus.

ft:
libFuzzer uses different signals to evaluate the code coverage: edge coverage, edge counters, value profiles, indirect caller/callee pairs, etc. These signals combined are called features (ft:).

corp:
Number of entries in the current in-memory test corpus and its size in bytes.

lim:
Current limit on the length of new entries in the corpus. Increases over time until the max length (-max_len) is reached.

exec/s:
Number of fuzzer iterations per second.

rss:
Current memory consumption.
For NEW and REDUCE events, the output line also includes information about the mutation operation that produced the new input:

L:
Size of the new input in bytes.

[xpe]

Closing this because I've removed fuzz_methods as of 85961d7 which adds validate() to the list of methods that get fuzzed. The new fuzzer file is called rwsv.rs meaning "read, write, seek, validate".

[xpe]

Update: the fuzz target is now called fuzz_rwsv as of 985c682.