Invalid free() in nDPI's serializer interface.

[utoni]

While upgrading nDPIds libnDPI, I've encuntered a memory error.

=================================================================
==109637==ERROR: AddressSanitizer: attempting free on address which was not malloc()-ed: 0x62d000064408 in thread T1
    #0 0x7f33b2f73b6f in __interceptor_free ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:123
    #1 0x5569a30fc4b2 in ndpi_term_serializer /home/toni/git/nDPId/libnDPI/src/lib/ndpi_serializer.c:435
    #2 0x5569a3066287 in free_workflow /home/toni/git/nDPId/nDPId.c:1469
    #3 0x5569a308a5e8 in free_reader_threads /home/toni/git/nDPId/nDPId.c:4734
    #4 0x5569a309be27 in nDPId_mainloop_thread /home/toni/git/nDPId/nDPId-test.c:1209
    #5 0x7f33b23b4ea6 in start_thread nptl/pthread_create.c:477
    #6 0x7f33b22d4a2e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0xfba2e)

0x62d000064408 is located 8 bytes inside of 33800-byte region [0x62d000064400,0x62d00006c808)
allocated by thread T1 here:
    #0 0x7f33b2f73e8f in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
    #1 0x5569a30630ef in ndpi_malloc_wrapper /home/toni/git/nDPId/nDPId.c:1139
    #2 0x5569a30f70c5 in ndpi_calloc /home/toni/git/nDPId/libnDPI/src/lib/ndpi_memory.c:67
    #3 0x5569a30f8b88 in ndpi_init_serializer_buffer /home/toni/git/nDPId/libnDPI/src/lib/ndpi_serializer.c:202
    #4 0x5569a30fc65e in ndpi_init_serializer_ll /home/toni/git/nDPId/libnDPI/src/lib/ndpi_serializer.c:221
    #5 0x5569a3064aac in init_workflow /home/toni/git/nDPId/nDPId.c:1327
    #6 0x5569a3066919 in setup_reader_threads /home/toni/git/nDPId/nDPId.c:1544
    #7 0x5569a309a097 in nDPId_mainloop_thread /home/toni/git/nDPId/nDPId-test.c:1156
    #8 0x7f33b23b4ea6 in start_thread nptl/pthread_create.c:477

Thread T1 created by T0 here:
    #0 0x7f33b2f1f2a2 in __interceptor_pthread_create ../../../../src/libsanitizer/asan/asan_interceptors.cpp:214
    #1 0x5569a309c584 in main /home/toni/git/nDPId/nDPId-test.c:1307
    #2 0x7f33b21fcd09 in __libc_start_main ../csu/libc-start.c:308

Seems like a free to an invalid memory block. Double free? Dangling pointer? Investigation ongoing.