Crash backtrace

alloc: invalid block: 0x1d09520: 20 1
Aborted (core dumped)

Program terminated with signal SIGABRT, Aborted.
#0  0x00007f7e4b07a849 in raise () from /lib64/libc.so.6
(gdb) bt
#0  0x00007f7e4b07a849 in raise () from /lib64/libc.so.6
#1  0x00007f7e4b07bcd8 in abort () from /lib64/libc.so.6
#2  0x0000000000563023 in Tcl_PanicVA (
    format=0x61c130 "alloc: invalid block: %p: %x %x", argList=0x7fffb3a21768)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclPanic.c:123
#3  0x00000000005630c4 in Tcl_Panic (
    format=0x61c130 "alloc: invalid block: %p: %x %x")
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclPanic.c:153
#4  0x0000000000586ae0 in Ptr2Block (ptr=0x1a78530 "@\205\240\001")
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclThreadAlloc.c:780
#5  0x000000000058617c in TclpFree (ptr=0x1a78530 "@\205\240\001")
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclThreadAlloc.c:406
#6  0x00000000005b2e43 in ReleaseClassContents (interp=0x19b5c10, 
    oPtr=0x1a09a40)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclOO.c:992
#7  0x00000000005b2997 in ObjectRenamedTrace (clientData=0x1a09a40, 
    interp=0x19b5c10, oldName=0x1a10ee0 "::oo::class", newName=0x0, 
    flags=16512)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclOO.c:875
#8  0x000000000043a310 in CallCommandTraces (iPtr=0x19b5c10, cmdPtr=0x1a09b40, 
    oldName=0x1a10ee0 "::oo::class", newName=0x0, flags=16512)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:3268
#9  0x0000000000439f85 in Tcl_DeleteCommandFromToken (interp=0x19b5c10, 
    cmd=0x1a09b40)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:3075
#10 0x0000000000558876 in TclTeardownNamespace (nsPtr=0x1a0bf50)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclNamesp.c:1133
#11 0x0000000000558749 in Tcl_DeleteNamespace (namespacePtr=0x1a0bf50)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclNamesp.c:1028
#12 0x00000000005589b9 in TclTeardownNamespace (nsPtr=0x19a1960)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclNamesp.c:1188
#13 0x0000000000437ac7 in DeleteInterpProc (interp=0x19b5c10)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:1449
#14 0x0000000000571190 in Tcl_EventuallyFree (clientData=0x19b5c10, 
    freeProc=0x4378c8 <DeleteInterpProc>)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclPreserve.c:296
#15 0x00000000004378c6 in Tcl_DeleteInterp (interp=0x19b5c10)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:1338
#16 0x00000000005306f3 in SlaveObjCmdDeleteProc (clientData=0x19b5c10)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclInterp.c:2715
#17 0x000000000043a07a in Tcl_DeleteCommandFromToken (interp=0x1909df0, 
    cmd=0x1a1d780)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:3130
#18 0x000000000052d127 in NRInterpCmd (clientData=0x0, interp=0x1909df0, 
    objc=3, objv=0x19176f0)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclInterp.c:860
#19 0x000000000043bbdb in Dispatch (data=0x1947988, interp=0x1909df0, result=0)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:4357
#20 0x000000000043bc69 in TclNRRunCallbacks (interp=0x1909df0, result=0, 
    rootPtr=0x0)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:4390
#21 0x000000000043b3c9 in Tcl_EvalObjv (interp=0x1909df0, objc=3, 
    objv=0x19176f0, flags=2097168)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:4121
#22 0x000000000043db68 in TclEvalEx (interp=0x1909df0, 
    script=0x199f160 "#!/usr/bin/tclkit\nset int [interp create]\n$int eval {\n    puts [package require Itcl]\n    itcl::class One {}\n    itcl::class Two {}\n}\ninterp delete $int\nputs \"Survived\"\n", numBytes=169, flags=0, line=8, 
    clNextOuter=0x0, 
    outerScript=0x199f160 "#!/usr/bin/tclkit\nset int [interp create]\n$int eval {\n    puts [package require Itcl]\n    itcl::class One {}\n    itcl::class Two {}\n}\ninterp delete $int\nputs \"Survived\"\n")
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclBasic.c:5259
#23 0x000000000054dc47 in Tcl_FSEvalFileEx (interp=0x1909df0, 
    pathPtr=0x19452b0, encodingName=0x0)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclIOUtil.c:1815
#24 0x0000000000556a59 in Tcl_MainEx (argc=-1, argv=0x7fffb3a22588, 
    appInitProc=0x405d96 <TclKit_AppInit>, interp=0x1909df0)
    at /home/sbron/src/kitcreator/tcl/build/tcl8.6.2/generic/tclMain.c:417
#25 0x0000000000405f69 in main ()