.. _memleak: ***************** Memory leaks ***************** Memory traces ============= VPP supports memory traces to help debug (suspected) memory leaks. Each allocation/deallocation is instrumented so that the number of allocations and current global allocated size is maintained for each unique allocation stack trace. Looking at a memory trace can help diagnose where memory is (over-)used, and comparing memory traces at different point in time can help diagnose if and where memory leaks happen. To enable memory traces on main-heap: .. code-block:: console $ vppctl memory-trace on main-heap To dump memory traces for analysis: .. code-block:: console $ vppctl show memory main-heap verbose Thread 0 vpp_main base 0x7fffb6422000, size 1g, locked, unmap-on-destroy, name 'main heap' page stats: page-size 4K, total 262144, mapped 30343, not-mapped 231801 numa 0: 30343 pages, 118.53m bytes total: 1023.99M, used: 115.49M, free: 908.50M, trimmable: 908.48M free chunks 451 free fastbin blks 0 max total allocated 1023.99M Bytes Count Sample Traceback 31457440 1 0x7fffbb31ad00 clib_mem_alloc_aligned_at_offset + 0x80 clib_mem_alloc_aligned + 0x26 alloc_aligned_8_8 + 0xe1 clib_bihash_instantiate_8_8 + 0x76 clib_bihash_init2_8_8 + 0x2ec clib_bihash_init_8_8 + 0x6a l2fib_table_init + 0x54 set_int_l2_mode + 0x89 int_l3 + 0xb4 vlib_cli_dispatch_sub_commands + 0xeee vlib_cli_dispatch_sub_commands + 0xc62 vlib_cli_dispatch_sub_commands + 0xc62 266768 5222 0x7fffbd79f978 clib_mem_alloc_aligned_at_offset + 0x80 vec_resize_allocate_memory + 0xa8 _vec_resize_inline + 0x240 unix_cli_file_add + 0x83d unix_cli_listen_read_ready + 0x10b linux_epoll_input_inline + 0x943 linux_epoll_input + 0x39 dispatch_node + 0x336 vlib_main_or_worker_loop + 0xbf1 vlib_main_loop + 0x1a vlib_main + 0xae7 thread0 + 0x3e .... libc memory traces ================== Internal VPP memory allocations rely on VPP main-heap, however when using external libraries, esp. in plugins (e.g. OpenSSL library used by the IKEv2 plugin), those external libraries usually manages memory using the standard libc malloc()/free()/... calls. This, in turn, makes use of the default libc heap. VPP has no knowledge of this heap and tools such as memory traces cannot be used. In order to enable the use of standard VPP debugging tools, this library replaces standard libc memory management calls with version using VPP main-heap. To use it, you need to use the `LD_PRELOAD` mechanism, e.g. .. code-block:: console ~# LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libvppmem_preload.so /usr/bin/vpp -c /etc/vpp/startup.conf You can then use tools such as memory traces as usual.