added SO link about rand for clarification

domenukk · domenukk · commit 92b1f9cf36e7 · 2020-08-31T12:11:38.000+02:00
diff --git a/include/afl-fuzz.h b/include/afl-fuzz.h
@@ -1027,7 +1027,9 @@ static inline u32 rand_below(afl_state_t *afl, u32 limit) {
 
   }
 
-  /* Modulo is biased - we don't want our fuzzing to be biased so let's do it right. */
+  /* Modulo is biased - we don't want our fuzzing to be biased so let's do it right, see
+  https://stackoverflow.com/questions/10984974/why-do-people-say-there-is-modulo-bias-when-using-a-random-number-generator
+  */
   u64 unbiased_rnd; 
   do {
     unbiased_rnd = rand_next(afl);

Original file line number	Diff line number	Diff line change
`@@ -1027,7 +1027,9 @@ static inline u32 rand_below(afl_state_t *afl, u32 limit) {`
`1027`	`1027`
`1028`	`1028`	`}`
`1029`	`1029`
`1030`		`- /* Modulo is biased - we don't want our fuzzing to be biased so let's do it right. */`
	`1030`	`+ /* Modulo is biased - we don't want our fuzzing to be biased so let's do it right, see`
	`1031`	`+ https://stackoverflow.com/questions/10984974/why-do-people-say-there-is-modulo-bias-when-using-a-random-number-generator`
	`1032`	`+ */`
`1031`	`1033`	`u64 unbiased_rnd;`
`1032`	`1034`	`do {`
`1033`	`1035`	`unbiased_rnd = rand_next(afl);`