Invalid write of size 4
   at 0x........: main (custom_alloc.c:79)
   by 0x........: __libc_start_main (...libc...)
   by 0x........: ...
   Address 0x........ is 48 bytes inside a block of size 100000 client-defined
   at 0x........: get_superblock (custom_alloc.c:25)
   by 0x........: custom_alloc (custom_alloc.c:40)
   by 0x........: main (custom_alloc.c:76)
   by 0x........: __libc_start_main (...libc...)

Invalid free() / delete / delete[]
   at 0x........: custom_free (custom_alloc.c:54)
   by 0x........: main (custom_alloc.c:83)
   by 0x........: __libc_start_main (...libc...)
   by 0x........: ...
   Address 0x........ is not stack'd, malloc'd or free'd

Mismatched free() / delete / delete []
   at 0x........: custom_free (custom_alloc.c:54)
   by 0x........: main (custom_alloc.c:86)
   by 0x........: __libc_start_main (...libc...)
   by 0x........: ...
   Address 0x........ is 0 bytes inside a block of size 40 alloc'd
   at 0x........: malloc (vg_replace_malloc.c:...)
   by 0x........: main (custom_alloc.c:85)
   by 0x........: __libc_start_main (...libc...)
   by 0x........: ...

Invalid read of size 4
   at 0x........: main (custom_alloc.c:89)
   by 0x........: __libc_start_main (...libc...)
   by 0x........: ...
   Address 0x........ is 8 bytes inside a block of size 100000 client-defined
   at 0x........: get_superblock (custom_alloc.c:25)
   by 0x........: custom_alloc (custom_alloc.c:40)
   by 0x........: main (custom_alloc.c:76)
   by 0x........: __libc_start_main (...libc...)

ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 0 from 0)
malloc/free: in use at exit: 40 bytes in 1 blocks.
malloc/free: 3 allocs, 3 frees, 120 bytes allocated.
For a detailed leak analysis,  rerun with: --leak-check=yes
For counts of detected errors, rerun with: -v