I found an issue in the implementation of atomic read and atomic write operations in ghc-prim. I am working on a fix for powerpc64 and
#12537: Parallel cabal builds Segmentation Fault on PowerPC 64-bit -------------------------------------+------------------------------------- Reporter: michelmno | Owner: trommler Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: powerpc64 Type of failure: Incorrect result | Test Case: at runtime | Blocked By: 12469 | Blocking: Related Tickets: | Differential Rev(s): Phab:D3984 Wiki Page: | -------------------------------------+------------------------------------- Changes (by trommler): * status: new => patch * differential: => Phab:D3984 Comment: Replying to [comment:11 trommler]: powerpc64le. Phab:3984 improves the situation a lot on an old PowerMac the segfault occurs only on every other run where before this patch I would see a segfault on almost all build attempts. The correctness issue I found in `libraries/ghc-prim/cbits/atomic.c` affects all platforms that are using the fallback functions `hs_atomicread*` and `hs_atomicwrite`. I will create a separate ticket for that. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12537#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler