GHCi HEAD segfaults upon startup with a prof build

After building GHC HEAD using a mk/build.mk file with the following settings:

BuildFlavour = prof
GhcStage2HcOpts    = -O0 $(GhcFAsm) -fprof-auto -DDEBUG

I find myself knee-deep in segfault town:

$ inplace/bin/ghc-stage2 --interactive
GHCi, version 8.3.20170726: http://www.haskell.org/ghc/  :? for help
Segmentation fault (core dumped)

Welp.

Here's what happens when I run it through gdb:

$ gdb inplace/lib/bin/ghc-stage2
GNU gdb (Ubuntu 7.7.1-0ubuntu5~14.04.2) 7.7.1
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from inplace/lib/bin/ghc-stage2...done.
(gdb) r -B"/u/rgscott/Software/ghc2/inplace/lib" --interactive
Starting program: /home/rgscott/Software/ghc2/inplace/lib/bin/ghc-stage2 -B"/u/rgscott/Software/ghc2/inplace/lib" --interactive
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff635e700 (LWP 13161)]
[New Thread 0x7ffff5b5d700 (LWP 13162)]
[New Thread 0x7ffff535c700 (LWP 13163)]
[New Thread 0x7ffff4b5b700 (LWP 13164)]
GHCi, version 8.3.20170726: http://www.haskell.org/ghc/  :? for help

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff4b5b700 (LWP 13164)]
0x000000000514ecb3 in interpretBCO (cap=0x64b9fc0 <MainCapability>)
    at rts/Interpreter.c:743
743                 if (get_itbl(UNTAG_CLOSURE(pap->fun))->type != BCO) {

Trac metadata

Trac field	Value
Version	8.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	highest
Resolution	Unresolved
Component	Compiler
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