#12690: Segmentation fault in GHC runtime system under low memory with USE_LARGE_ADDRESS_SPACE -----------------------------------+-------------------------------------- Reporter: pggiarrusso | Owner: (none) Type: bug | Status: new Priority: high | Milestone: Component: Runtime System | Version: 8.0.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -----------------------------------+-------------------------------------- Comment (by allbery_b): The specific circumstances that would lead to this are: - runtime does an `madvise` to request a new page. This returns success/fail of the request, but the OS does not actually assign a page until it is needed - if the page can't actually be allocated at the time of first use (which likely means first write to it), the process will be sent `SIGSEGV` This is one reason other projects don't use this style of memory management any more (somewhat infamously, the original Bourne shell did memory allocation this way, but instead of `madvise` --- which didn't exist yet --- it just caught the `SIGSEGV` and called `brk` to increase the allocated address space). That sort-of worked (except on MC68000; Sun had to rewrite the Bourne shell's memory manager) on non-demand paged systems, but delayed-until-use allocation on demand paged systems means `SEGV` is the only way to know an allocation failed. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12690#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler