#14915: T2783 fails with the threaded1 way --------------------------------------+---------------------------------- Reporter: alpmestan | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 8.5 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: Runtime crash Test Case: T2783 | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+---------------------------------- When running `./validate --slow` the other day, I saw the XXX test failing with the `threaded1` way. Instead of detecting the loop and aborting with an informative message, we get an assertion failure in the `rts/ThreadPaused.c:threadPaused` function. The program: {{{#!hs main = print $ do x <- [ 0 .. 5 ] ; let { y = 5 - y } ; return y }}} The output: {{{ =====> T2783(threaded1) 1 of 1 [0, 0, 0] cd "./rts/T2783.run" && "/home/alp/ghc/inplace/test spaces/ghc-stage2" -o T2783 T2783.hs -dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -fdiagnostics- color=never -fno-diagnostics-show-caret -dno-debug-output -threaded -debug cd "./rts/T2783.run" && ./T2783 Wrong exit code for T2783(threaded1)(expected 1 , actual 134 ) Stderr ( T2783 ): T2783: internal error: ASSERTION FAILED: file rts/ThreadPaused.c, line 314 (GHC version 8.5.20180306 for x86_64_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug Aborted (core dumped) *** unexpected failure for T2783(threaded1) }}} The code for the corresponding assertion: {{{#!c // We should never have made it here in the event of blackholes that // we already own; they should have been marked when we blackholed // them and consequently we should have stopped our stack walk // above. ASSERT(!((bh_info == &stg_BLACKHOLE_info) && (((StgInd*)bh)->indirectee == (StgClosure*)tso))); }}} This seems to be an actual problem, hence this ticket. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14915 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler