#10080: Recusive IO actions crash with segmentation fault -------------------------------------+------------------------------------- Reporter: nakal | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: FreeBSD | Architecture: x86_64 Type of failure: Runtime crash | (amd64) Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Description changed by nakal: Old description:

I am learning Haskell and wrote a program that writes some strings to stdout infinitely by recursing in an IO action. It seems such a simple construct crashes on FreeBSD when Ctrl+C is pressed to interrupt it.

I have been able to reduce it to a simple case like this:

{{{#!hs main = do putStrLn "hello world" main }}}

I compiled it with {{{ ghc --make hello.hs }}}

Then pressed Ctrl+C and immediately got: {{{ [...] hello world hello world hello world hello world ^CSegmentation fault (core dumped) }}}

Here is the backtrace of the crash:

{{{ (gdb) bt #0 0x000000000047cdd7 in generic_handler () #1 0x000000080147c467 in swapcontext () from /lib/libthr.so.3 #2 0x000000080147c062 in sigaction () from /lib/libthr.so.3 #3 <signal handler called> #4 0x00000008017d7b7a in select () from /lib/libc.so.7 #5 0x0000000801479b32 in select () from /lib/libthr.so.3 #6 0x000000000043cb13 in fdReady () #7 0x000000000044751c in base_GHCziIOziFD_zdwa3_info () #8 0x0000000000000000 in ?? () }}}

New description: I am learning Haskell and wrote a program that writes some strings to stdout infinitely by recursing in an IO action. It seems such a simple construct crashes on FreeBSD when Ctrl+C is pressed to interrupt it. I have been able to reduce it to a simple case like this: {{{#!hs main = do putStrLn "hello world" main }}} I compiled it with {{{ ghc --make hello.hs }}} Ran it and then pressed Ctrl+C and immediately got: {{{ [...] hello world hello world hello world hello world ^CSegmentation fault (core dumped) }}} Here is the backtrace of the crash: {{{ (gdb) bt #0 0x000000000047cdd7 in generic_handler () #1 0x000000080147c467 in swapcontext () from /lib/libthr.so.3 #2 0x000000080147c062 in sigaction () from /lib/libthr.so.3 #3 <signal handler called> #4 0x00000008017d7b7a in select () from /lib/libc.so.7 #5 0x0000000801479b32 in select () from /lib/libthr.so.3 #6 0x000000000043cb13 in fdReady () #7 0x000000000044751c in base_GHCziIOziFD_zdwa3_info () #8 0x0000000000000000 in ?? () }}} Operating system version is: FreeBSD 10.1-RELEASE-p5 (GENERIC) -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10080#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10080: Recusive IO actions crash with segmentation fault -------------------------------------+------------------------------------- Reporter: nakal | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: FreeBSD | Architecture: x86_64 Type of failure: Runtime crash | (amd64) Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by nakal): This is not a virtualized system and the segfaults are reproducible without any exceptions. Here comes some data about it: CPU: Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz (3503.51-MHz K8-class CPU) FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs FreeBSD/SMP: 1 package(s) x 4 core(s) x 2 SMT threads real memory = 17179869184 (16384 MB) At work I have some other system, also running FreeBSD-10.1-RELEASE on a AMD 3-core processor with 8 GB RAM. It also segfaults. Notice: I also have actually some other race conditions with signals on FreeBSD/amd64 with GHC-compiled programs that happen in Xmonad and are described here: https://code.google.com/p/xmonad/issues/detail?id=576#c6start=100 I would like to add it to the bugtracker as a separate problem (I still don't know how to describe it precisely enough for a bug report, but I am almost sure it belongs here rather than the Xmonad bugtracker), but looking at all this, it appears to me that GHC-binaries have some more problems with signals and threads on FreeBSD/amd64. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10080#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10080: Recusive IO actions crash with segmentation fault -------------------------------------+------------------------------------- Reporter: nakal | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: FreeBSD | Architecture: x86_64 Type of failure: Runtime crash | (amd64) Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by pgj): All right, here is a more detailed backtrace, just for the record: {{{ #0 0x00000000004801d7 in generic_handler () #1 0x00000008014810d6 in handle_signal (actp=0x7fffffffa418, sig=2, info=0x10006, ucp=0x7fffffffa480) at /usr/src/lib/libthr/thread/thr_sig.c:238 #2 0x0000000801480ad5 in thr_sighandler (sig=2, info=0x10006, _ucp=0x7fffffffa480) at /usr/src/lib/libthr/thread/thr_sig.c:183 #3 <signal handler called> #4 select () at select.S:3 #5 0x000000080147ce95 in __select (numfds=2, readfds=0x7fffffffa930, writefds=0x7fffffffa9b0, exceptfds=0x0, timeout=0x7fffffffa920) at /usr/src/lib/libthr/thread/thr_syscalls.c:561 #6 0x00000000004534f3 in fdReady () #7 0x0000000000458e54 in base_GHCziIOziFD_zdwa3_info () #8 0x0000000000000000 in ?? () }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10080#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10080: Recusive IO actions crash with segmentation fault -------------------------------------+------------------------------------- Reporter: nakal | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: FreeBSD | Architecture: x86_64 Type of failure: Runtime crash | (amd64) Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by pgj): Yeah, I have also managed to reproduce the crash on my dual-core AMD C-50 netbook (with 10.1-RELEASE), which is probably much slower than all of these machines. In the meantime, I have contacted Kostik Belousov (kib@), who maintains {{{libthr(3)}}} these days, but unfortunately he could not yet reproduce the problem on any of his machines. Although, this might be because he runs 10-STABLE. Perhaps could you please try a recent revision of the {{{stable/10}}} branch and report if the problem still persists there? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10080#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10080: Recusive IO actions crash with segmentation fault -------------------------------------+------------------------------------- Reporter: nakal | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: FreeBSD | Architecture: x86_64 Type of failure: Runtime crash | (amd64) Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by pgj): That is great! So may I close this ticket? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10080#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10080: Recusive IO actions crash with segmentation fault -------------------------------------+------------------------------------- Reporter: nakal | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: fixed | Keywords: Operating System: FreeBSD | Architecture: x86_64 Type of failure: Runtime crash | (amd64) Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by pgj): * status: new => closed * resolution: => fixed -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10080#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler