*** Error in `ruby': free(): invalid next size (fast): 0x00000000021a2830 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7f7d6203b7e5]
/lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7f7d6204437a]
/lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7f7d6204853c]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(ruby_xfree+0x2d)[0x7f7d6246724d]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0x106dea)[0x7f7d62494dea]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0xd9deb)[0x7f7d62467deb]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0xda1f3)[0x7f7d624681f3]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0xdabb3)[0x7f7d62468bb3]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0xdb75f)[0x7f7d6246975f]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0x2444f7)[0x7f7d625d24f7]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0x256f83)[0x7f7d625e4f83]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0x24d042)[0x7f7d625db042]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(rb_vm_exec+0xb4)[0x7f7d625e11d4]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(+0xbe34a)[0x7f7d6244c34a]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(ruby_exec_node+0x1d)[0x7f7d6244e22d]
/home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6(ruby_run_node+0x2e)[0x7f7d624520de]
ruby[0x4009af]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f7d61fe4830]
ruby(_start+0x29)[0x4009f9]
======= Memory map: ========
00400000-00401000 r-xp 00000000 08:01 1906677                            /home/max/.rvm/rubies/ruby-head/bin/ruby
00600000-00601000 r--p 00000000 08:01 1906677                            /home/max/.rvm/rubies/ruby-head/bin/ruby
00601000-00602000 rw-p 00001000 08:01 1906677                            /home/max/.rvm/rubies/ruby-head/bin/ruby
01db2000-01dd3000 rw-p 00000000 00:00 0                                  [heap]
01dd3000-022c5000 rw-p 00000000 00:00 0                                  [heap]
7f7d58000000-7f7d58021000 rw-p 00000000 00:00 0 
7f7d58021000-7f7d5c000000 ---p 00000000 00:00 0 
7f7d5e0ad000-7f7d5e0c3000 r-xp 00000000 08:01 922597                     /lib/x86_64-linux-gnu/libgcc_s.so.1
7f7d5e0c3000-7f7d5e2c2000 ---p 00016000 08:01 922597                     /lib/x86_64-linux-gnu/libgcc_s.so.1
7f7d5e2c2000-7f7d5e2c3000 rw-p 00015000 08:01 922597                     /lib/x86_64-linux-gnu/libgcc_s.so.1
7f7d5e2c3000-7f7d5e2c6000 r-xp 00000000 08:01 1908344                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/coverage.so
7f7d5e2c6000-7f7d5e4c5000 ---p 00003000 08:01 1908344                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/coverage.so
7f7d5e4c5000-7f7d5e4c6000 r--p 00002000 08:01 1908344                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/coverage.so
7f7d5e4c6000-7f7d5e4c7000 rw-p 00003000 08:01 1908344                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/coverage.so
7f7d5e4c7000-7f7d5e4cd000 r-xp 00000000 08:01 1908343                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/etc.so
7f7d5e4cd000-7f7d5e6cc000 ---p 00006000 08:01 1908343                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/etc.so
7f7d5e6cc000-7f7d5e6cd000 r--p 00005000 08:01 1908343                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/etc.so
7f7d5e6cd000-7f7d5e6ce000 rw-p 00006000 08:01 1908343                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/etc.so
7f7d5e6ce000-7f7d5e6d7000 r-xp 00000000 08:01 1908349                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/stringio.so
7f7d5e6d7000-7f7d5e8d6000 ---p 00009000 08:01 1908349                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/stringio.so
7f7d5e8d6000-7f7d5e8d7000 r--p 00008000 08:01 1908349                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/stringio.so
7f7d5e8d7000-7f7d5e8d8000 rw-p 00009000 08:01 1908349                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/stringio.so
7f7d5e8d8000-7f7d5e8da000 r-xp 00000000 08:01 2036243                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/trans/transdb.so
7f7d5e8da000-7f7d5eada000 ---p 00002000 08:01 2036243                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/trans/transdb.so
7f7d5eada000-7f7d5eadb000 r--p 00002000 08:01 2036243                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/trans/transdb.so
7f7d5eadb000-7f7d5eadc000 rw-p 00003000 08:01 2036243                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/trans/transdb.so
7f7d5eadc000-7f7d5eade000 r-xp 00000000 08:01 2036266                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/encdb.so
7f7d5eade000-7f7d5ecdd000 ---p 00002000 08:01 2036266                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/encdb.so
7f7d5ecdd000-7f7d5ecde000 r--p 00001000 08:01 2036266                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/encdb.so
7f7d5ecde000-7f7d5ecdf000 rw-p 00002000 08:01 2036266                    /home/max/.rvm/rubies/ruby-head/lib/ruby/2.6.0/x86_64-linux/enc/encdb.so
7f7d5ecdf000-7f7d60ce8000 rw-p 00000000 00:00 0 
7f7d60ce8000-7f7d60fc0000 r--p 00000000 08:01 1574444                    /usr/lib/locale/locale-archive
7f7d60fc0000-7f7d610c8000 r-xp 00000000 08:01 920080                     /lib/x86_64-linux-gnu/libm-2.23.so
7f7d610c8000-7f7d612c7000 ---p 00108000 08:01 920080                     /lib/x86_64-linux-gnu/libm-2.23.so
7f7d612c7000-7f7d612c8000 r--p 00107000 08:01 920080                     /lib/x86_64-linux-gnu/libm-2.23.so
7f7d612c8000-7f7d612c9000 rw-p 00108000 08:01 920080                     /lib/x86_64-linux-gnu/libm-2.23.so
7f7d612c9000-7f7d612d2000 r-xp 00000000 08:01 920128                     /lib/x86_64-linux-gnu/libcrypt-2.23.so
7f7d612d2000-7f7d614d1000 ---p 00009000 08:01 920128                     /lib/x86_64-linux-gnu/libcrypt-2.23.so
7f7d614d1000-7f7d614d2000 r--p 00008000 08:01 920128                     /lib/x86_64-linux-gnu/libcrypt-2.23.so
7f7d614d2000-7f7d614d3000 rw-p 00009000 08:01 920128                     /lib/x86_64-linux-gnu/libcrypt-2.23.so
7f7d614d3000-7f7d61501000 rw-p 00000000 00:00 0 
7f7d61501000-7f7d61504000 r-xp 00000000 08:01 920092                     /lib/x86_64-linux-gnu/libdl-2.23.so
7f7d61504000-7f7d61703000 ---p 00003000 08:01 920092                     /lib/x86_64-linux-gnu/libdl-2.23.so
7f7d61703000-7f7d61704000 r--p 00002000 08:01 920092                     /lib/x86_64-linux-gnu/libdl-2.23.so
7f7d61704000-7f7d61705000 rw-p 00003000 08:01 920092                     /lib/x86_64-linux-gnu/libdl-2.23.so
7f7d61705000-7f7d61784000 r-xp 00000000 08:01 1583894                    /usr/lib/x86_64-linux-gnu/libgmp.so.10.3.0
7f7d61784000-7f7d61983000 ---p 0007f000 08:01 1583894                    /usr/lib/x86_64-linux-gnu/libgmp.so.10.3.0
7f7d61983000-7f7d61984000 r--p 0007e000 08:01 1583894                    /usr/lib/x86_64-linux-gnu/libgmp.so.10.3.0
7f7d61984000-7f7d61985000 rw-p 0007f000 08:01 1583894                    /usr/lib/x86_64-linux-gnu/libgmp.so.10.3.0
7f7d61985000-7f7d6198c000 r-xp 00000000 08:01 920126                     /lib/x86_64-linux-gnu/librt-2.23.so
7f7d6198c000-7f7d61b8b000 ---p 00007000 08:01 920126                     /lib/x86_64-linux-gnu/librt-2.23.so
7f7d61b8b000-7f7d61b8c000 r--p 00006000 08:01 920126                     /lib/x86_64-linux-gnu/librt-2.23.so
7f7d61b8c000-7f7d61b8d000 rw-p 00007000 08:01 920126                     /lib/x86_64-linux-gnu/librt-2.23.so
7f7d61b8d000-7f7d61ba5000 r-xp 00000000 08:01 920086                     /lib/x86_64-linux-gnu/libpthread-2.23.so
7f7d61ba5000-7f7d61da4000 ---p 00018000 08:01 920086                     /lib/x86_64-linux-gnu/libpthread-2.23.so
7f7d61da4000-7f7d61da5000 r--p 00017000 08:01 920086                     /lib/x86_64-linux-gnu/libpthread-2.23.so
7f7d61da5000-7f7d61da6000 rw-p 00018000 08:01 920086                     /lib/x86_64-linux-gnu/libpthread-2.23.so
7f7d61da6000-7f7d61daa000 rw-p 00000000 00:00 0 
7f7d61daa000-7f7d61dc3000 r-xp 00000000 08:01 918057                     /lib/x86_64-linux-gnu/libz.so.1.2.8
7f7d61dc3000-7f7d61fc2000 ---p 00019000 08:01 918057                     /lib/x86_64-linux-gnu/libz.so.1.2.8
7f7d61fc2000-7f7d61fc3000 r--p 00018000 08:01 918057                     /lib/x86_64-linux-gnu/libz.so.1.2.8
7f7d61fc3000-7f7d61fc4000 rw-p 00019000 08:01 918057                     /lib/x86_64-linux-gnu/libz.so.1.2.8
7f7d61fc4000-7f7d62184000 r-xp 00000000 08:01 920088                     /lib/x86_64-linux-gnu/libc-2.23.so
7f7d62184000-7f7d62384000 ---p 001c0000 08:01 920088                     /lib/x86_64-linux-gnu/libc-2.23.so
7f7d62384000-7f7d62388000 r--p 001c0000 08:01 920088                     /lib/x86_64-linux-gnu/libc-2.23.so
7f7d62388000-7f7d6238a000 rw-p 001c4000 08:01 920088                     /lib/x86_64-linux-gnu/libc-2.23.so
7f7d6238a000-7f7d6238e000 rw-p 00000000 00:00 0 
7f7d6238e000-7f7d626de000 r-xp 00000000 08:01 1906679                    /home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6.0
7f7d626de000-7f7d628dd000 ---p 00350000 08:01 1906679                    /home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6.0
7f7d628dd000-7f7d628e3000 r--p 0034f000 08:01 1906679                    /home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6.0
7f7d628e3000-7f7d628e6000 rw-p 00355000 08:01 1906679                    /home/max/.rvm/rubies/ruby-head/lib/libruby.so.2.6.0
7f7d628e6000-7f7d628f8000 rw-p 00000000 00:00 0 
7f7d628f8000-7f7d6291e000 r-xp 00000000 08:01 920084                     /lib/x86_64-linux-gnu/ld-2.23.so
7f7d62994000-7f7d62af6000 rw-p 00000000 00:00 0 
7f7d62af6000-7f7d62afc000 rw-p 00000000 00:00 0 
7f7d62b1b000-7f7d62b1c000 rw-p 00000000 00:00 0 
7f7d62b1c000-7f7d62b1d000 rw-p 00000000 00:00 0 
7f7d62b1d000-7f7d62b1e000 r--p 00025000 08:01 920084                     /lib/x86_64-linux-gnu/ld-2.23.so
7f7d62b1e000-7f7d62b1f000 rw-p 00026000 08:01 920084                     /lib/x86_64-linux-gnu/ld-2.23.so
7f7d62b1f000-7f7d62b20000 rw-p 00000000 00:00 0 
7fff81048000-7fff81847000 rw-p 00000000 00:00 0                          [stack]
7fff819d1000-7fff819d4000 r--p 00000000 00:00 0                          [vvar]
7fff819d4000-7fff819d6000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]