#7629: segmentation fault in compiled program, involves gtk, selinux -----------------------------------------------------------------+---------- Reporter: wgmitchener | Owner: simonmar Type: bug | Status: infoneeded Priority: high | Milestone: 7.6.2 Component: Runtime System | Version: 7.4.2 Keywords: segmentation fault, multithreading, selinux, gtk | Os: Linux Architecture: x86 | Failure: Runtime crash Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | -----------------------------------------------------------------+---------- Comment(by wgmitchener): I just added a minimal example that doesn't need GTK -- see attachment ghc-bug-002.zip. It's a simple case of Haskell calling into C calling back into Haskell. I'm using Fedora 17. The program works fine when compiled under GHC 7.0.4: {{{ Setting callback set_callback: at top set_callback: p_callback = (nil) set_callback: callback_data = 0 set_callback: p_finalizer = (nil) set_callback: new pointer values: set_callback: p_callback = 0xb77ee02c set_callback: callback_data = 10 set_callback: p_finalizer = 0xb77ee00c set_callback: done Invoking callback invoke_callback: at top invoke_callback: p_callback = 0xb77ee02c invoke_callback: callback_data = 10 invoke_callback: p_finalizer = 0xb77ee00c invoke_callback: calling callback invoke_callback: return value is 11 invoke_callback: done Clearing callback clear_callback: at top clear_callback: p_callback = 0xb77ee02c clear_callback: callback_data = 10 clear_callback: p_finalizer = 0xb77ee00c clear_callback: finalizing callback clear_callback: p_callback = (nil) clear_callback: callback_data = 0 clear_callback: p_finalizer = (nil) clear_callback: done }}} But it seg faults under GHC 7.4.2. {{{ Setting callback set_callback: at top set_callback: p_callback = (nil) set_callback: callback_data = 0 set_callback: p_finalizer = (nil) set_callback: new pointer values: set_callback: p_callback = 0xb77d702c set_callback: callback_data = 10 set_callback: p_finalizer = 0xb77d700c set_callback: done Invoking callback invoke_callback: at top invoke_callback: p_callback = 0xb77d702c invoke_callback: callback_data = 10 invoke_callback: p_finalizer = 0xb77d700c invoke_callback: calling callback Segmentation fault }}} On the Ubuntu 12.10 live image, after installing GHC 7.4.2, it runs with no seg fault. However, Ubuntu doesn't use SELinux. Maybe the thunk that goes back into Haskell is jumping to the wrong address, a few bytes before the actual function, and the instructions there are basically harmless, but SELinux catches them? -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7629#comment:17 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler