Compiled program crashes
I have a program which compiles fine, but the resulting executable crashes. First the steps to reproduce:
git clone email@example.com:waldheinz/bling.git git checkout e2bad3ca6be2409386d28796997709318cf6ff64 cabal configure cabal build ./dist/build/bling/bling examples/cornell-box-underwater.bling
This will result in either a segfault or produce an "internal error" message, at least for me and two other who tried it as well. The error message is
bling: internal error: scavenge_one: strange object -1083673327 (GHC version 7.7.20120823 for x86_64_unknown_linux)
The "strange object" varies. Some random observations which might be useful:
- this happens with GHC 7.4.1 and a fresh compile of HEAD (GHC version 7.7.20120823)
- I sanitized the code to be completely free of unsafe* function calls. Before, there was quite some unsafe array reading/writing using the vector package. This did not change anything, but the revision above reflects this "safe" state, just in case...
- the problem first occured when I change the SPPM.mkHash function to use the Utils.GrowVec type instead of lists for it's intermediate results.  GrowVec is basically a wrapper around a vector which doubles the size when space is exhausted.
- the optimization level does not seem to affect the problem (it occurs even with -O0 and everything else removed)
Running under GDB gives this stack trace:
#1 0x00000031d12370d8 in abort () from /lib64/libc.so.6 #2 0x0000000000cb4765 in rtsFatalInternalErrorFn () #3 0x0000000000cb48dd in barf () #4 0x0000000000cd30e9 in scavenge_one () #5 0x0000000000cd3645 in scavenge_mutable_list () #6 0x0000000000cd3835 in scavenge_capability_mut_lists () #7 0x0000000000cb98bc in GarbageCollect () #8 0x0000000000cac043 in scheduleDoGC.isra.20 () #9 0x0000000000cacabf in scheduleWaitThread () #10 0x0000000000cb683e in real_main () #11 0x0000000000cb693a in hs_main () #12 0x0000000000407003 in main ()
I'm currently trying to debug this further, but my abilities on this front are limited...