#15729: Static GHCi can segfault when accessing .bss section in C --------------------------------------+------------------------------- Reporter: watashi | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.6.1 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: GHCi crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+------------------------------- When an object file is statically linked, GHCi can return junk or segfault when trying to access data defined in .bss section via foreign call. {{{ watashi % ~/gao/ghc/inplace/bin/ghc-stage2 --info | grep Dynamic ,("Dynamic by default","NO") ,("GHC Dynamic","NO") watashi % cat bss.c int read_bss(int i) { static int bss[1 << 20]; return bss[i]; } watashi % ~/gao/ghc/inplace/bin/ghc-stage2 --interactive test.o GHCi, version 8.7.20180920: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/watashi/.ghci Prelude> :m + Foreign Foreign.C Prelude Foreign Foreign.C> foreign import ccall unsafe "read_bss" read_bss :: Int -> IO Int Prelude Foreign Foreign.C> read_bss 0 4294059519 Prelude Foreign Foreign.C> read_bss 1 65535 Prelude Foreign Foreign.C> mapM (read_bss . bit) [0 .. 19] zsh: segmentation fault (core dumped) ~/gao/ghc/inplace/bin/ghc-stage2 --interactive test.o }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15729 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler