GHC.Exts.traceEvent segfaults

When I call the GC.Exts.traceEvent function (argument: "hello") with event logging enabled (i.e., compiled with -eventlog and run with -ls) my program generates a segmentation fault. Here is the gdb backtrace:

#0  0x00007f3ad6744a2f in vfprintf () from /lib/libc.so.6
#1  0x00007f3ad677039a in vsnprintf () from /lib/libc.so.6
#2  0x00000000004476c4 in postLogMsg (eb=0x8160d0, type=19, 
    msg=0x7f3ad5d7e010 "hello", ap=0x0) at rts/eventlog/EventLog.c:403
#3  0x0000000000447853 in postUserMsg (cap=0x69b780, 
    msg=0x7f3ad5d7e010 "hello") at rts/eventlog/EventLog.c:433
#4  0x000000000043b012 in traceUserMsg (cap=0x69b780, 
    msg=0x7f3ad5d7e010 "hello") at rts/Trace.c:290
#5  0x000000000044e237 in stg_traceEventzh ()
#6  0x0000000000000000 in ?? ()

It's not at all clear to me what could be going wrong here.

Trac metadata

Trac field	Value
Version	6.12.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Runtime System
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