#13970: Segmentation fault inside threadPaused -------------------------------------+------------------------------------- Reporter: albertov | Owner: (none) Type: bug | Status: patch Priority: highest | Milestone: 8.2.1 Component: Runtime System | Version: 8.2.1-rc3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * priority: normal => highest * status: new => patch * milestone: => 8.2.1 Comment: I found the issue. I neglected to consider that the stack-pointer adjustment in the `AP_STACK` entry code also accounted for the words that we would later copy from the applied stack to the current thread's stack. Since the stack-pointer adjustment happened before we attempted to blackhole the `AP_STACK` closure, there was a small chance that we would suspend the thread with uninitialized content on its stack (specifically, if another thread beat us to blackholing the closure). This should be fixed by Phab:D3760. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13970#comment:26 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler