Segmentation fault when .prof file not writeable

To reproduce:

$ echo 'main = return ()' > Test.hs

$ touch Test.prof

$ chmod -w Test.prof

$ ghc -prof Test.hs
[1 of 1] Compiling Main             ( Test.hs, Test.o )
Linking Test ...

$ ./Test +RTS -hr{} -hc
Can't open profiling report file Test.prof
Segmentation fault (core dumped)

The warning is ok (maybe it should be an error?), but it shouldn't segfault.

Running ./Test +RTS -hr works fine.

http://downloads.haskell.org/\~ghc/master/users-guide/profiling.html\#rts-options-for-heap-profiling:

• -hc: Breaks down the graph by the cost-centre stack which produced the data.
• -hr⟨cc⟩: Restrict the profile to closures with retainer sets containing cost-centre stacks with one of the specified cost centres at the top.

Bug exists since dbef766c (2002):

- you can now restrict a heap profile to certain retainer sets,
  but still display by cost centre (or type, or closure or
  whatever).

Because it didn't update this code+comment introduced in db61851c (2001):

// The following line was added by Sung; retainer/LDV profiling may need
// two output files, i.e., <program>.prof/hp.
if (RtsFlags.ProfFlags.doHeapProfile == HEAP_BY_RETAINER)
    RtsFlags.ProfFlags.doHeapProfile = 0;

Another relevant commit a4e17de6:

Author: simonmar <unknown>
Date:   Wed Nov 28 15:42:26 2001 +0000

    [project @ 2001-11-28 15:42:26 by simonmar]
    Don't need the .prof file when LDV-profiling.

Trac metadata

Trac field	Value
Version	7.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Profiling
Test case
Differential revisions
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Architecture