DWARF unwind info is broken

As reported by bitonic and petermw on #ghc (April 2nd):

07:02 < bitonic> I'm trying to get a meaningful backtrace with DWARF, using 
                 <https://ghc.haskell.org/trac/ghc/wiki/DWARF> as a guide.  however, all I get is 
                 `Backtrace stopped: previous frame identical to this frame (corrupt stack?)`
07:03 < bitonic> I've re-built GHC 7.10.1 using `GhcRtsHcOpts += -g` and `GhcLibHcOpts += -g`, even if 
                 I'm not sure it's even necessary
07:04 < bitonic> are there any additional steps I should take?  or any way to make sure that the binary 
                 I'm generating is sane?

Trac metadata

Trac field	Value
Version	7.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler (Debugging)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	scpmw
Operating system
Architecture