#13633: testwsdeque failure on POWER8 -------------------------------------+------------------------------------- Reporter: trommler | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: Component: Runtime System | Version: 8.1 Resolution: | Keywords: SMP, ci- | breakage Operating System: Linux | Architecture: powerpc64 Type of failure: Runtime crash | Test Case: | rts/testwsdeque Blocked By: | Blocking: Related Tickets: | Differential Rev(s): ghc/ghc!445 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Marge Bot <ben+marge-bot@…>): In [changeset:"5c084e0468be46f5ab48b2c1669a7e4d4d0f3c43/ghc" 5c084e04/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="5c084e0468be46f5ab48b2c1669a7e4d4d0f3c43" RTS: Add missing memory barrier In the work stealing queue a load-load-barrier is required to ensure that a read of queue data cannot be reordered before a read of the bottom pointer into the queue. The added load-load-barrier ensures that the ordering of writes enforced at the end of `pushWSDeque` is also respected in the order of reads in `stealWSDeque_`. In other words, when reading `q->bottom` we want to make sure that we see the updates to `q->elements`. Fixes #13633 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13633#comment:9> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler