grep.3c3bdace.diagnosis.txt

If grep searches for a certain extended regular expression (-E ’(ˆ| )*( | $)’),
then it crashes with a coredump. When dfaanalyze allocates memory for
merged.elems (dfa.c:1728), it allocates insufficient memory because
merged.elems can grow to twice the original size (dfa.c:1455).  Then memory is
corrupted when the array is accessed out of bounds (dfa.c:1453). Only later the
program crashes because of the corrupted memory (dfa.c:1917). 

Examples of Correct Fixes: 
1) Allocate twice or 3x as much for merged.elems. 
2) Reallocate as needed. 

Example of Incorrect Fix: 
Always reset the number of elements (nelem) to 0 (Regression because we always
override the first element).