I think you find the problem.
Can you do another test to be sure?
In recover-src/extract_list.c,change the line 2015 form
toCode:g_ptr_array_add(argv_ptr, g_strdup("-xpGvf"));
(remove the 'v' flag)Code:g_ptr_array_add(argv_ptr, g_strdup("-xpGf"));
tar will write nothing, so it should not hang, amrecover will not show the list of files, but the extraction should succeed