See the valgrind log below.
==23619== Memcheck, a memory error detector
==23619== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==23619== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
==23619== Command: ./sub_main vit_normal.ppm
==23619==
==23619== Invalid read of size 8
==23619==    at 0x400BD9: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==  Address 0x543f03a is 10,362 bytes inside a block of size 10,368 alloc'd
==23619==    at 0x4C28BED: malloc (vg_replace_malloc.c:263)
==23619==    by 0x400B2D: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==
==23619== Invalid read of size 8
==23619==    at 0x400CB4: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==  Address 0x5446a7a is 10,362 bytes inside a block of size 10,368 alloc'd
==23619==    at 0x4C28BED: malloc (vg_replace_malloc.c:263)
==23619==    by 0x400B5A: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==
==23619== Invalid read of size 8
==23619==    at 0x400D10: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==  Address 0x5446a7d is 10,365 bytes inside a block of size 10,368 alloc'd
==23619==    at 0x4C28BED: malloc (vg_replace_malloc.c:263)
==23619==    by 0x400B5A: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==
==23619== Invalid read of size 8
==23619==    at 0x400DFF: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==  Address 0x54441ba is 10,362 bytes inside a block of size 10,368 alloc'd
==23619==    at 0x4C28BED: malloc (vg_replace_malloc.c:263)
==23619==    by 0x400B4B: main (in /tmp/A0B36APO-ullriher-r5I9/tests/sub_main)
==23619==
==23619==
==23619== HEAP SUMMARY:
==23619==     in use at exit: 0 bytes in 0 blocks
==23619==   total heap usage: 7 allocs, 7 frees, 43,176 bytes allocated
==23619==
==23619== All heap blocks were freed -- no leaks are possible
==23619==
==23619== For counts of detected and suppressed errors, rerun with: -v
==23619== ERROR SUMMARY: 9216 errors from 4 contexts (suppressed: 4 from 4)