[GHC] #13607: Panic with profiled compiler: Dynamic linker not initialised

23 Apr 2017

      #13607: Panic with profiled compiler: Dynamic linker not initialised
-------------------------------------+-------------------------------------
           Reporter:  RyanGlScott    |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 There are several Trac tickets floating around which mention this panic,
 including:

 * #9868 (ghc: panic! Dynamic linker not initialised)
 * #10355 (Dynamic linker not initialised)
 * #10919 (ghc: panic! (the 'impossible' happened) ... Dynamic linker not
 initialised)
 * #13137 (Dynamic linker not initialised.)
 * #13531 (GHC fails with "Dynamic linker not initialised" when -j is on
 and trying to load nonexistent .so file)

 However, none seem particularly simple to reproduce. I have a (marginally)
 easier way to trigger this panic. You'll need the following:

 * A copy of GHC HEAD built with the `prof` flavor. For reference, I am
 using GHC HEAD built against 1f4fd37efac4795493677d5df81c83d22eac5f74.
 * A single package built with `cabal-install`. For simplicity, I used
 `random`:

 {{{
 $ cabal install random-1.1 -w ~/Software/ghc3/inplace/bin/ghc-stage2
 }}}

 Once it's installed, you'll need to learn `random`'s package ID, which can
 be done with `ghc-pkg`. For instance:

 {{{
 3$ ~/Software/ghc3/inplace/bin/ghc-pkg describe random
 name: random
 version: 1.1
 id: random-1.1-Gnn89iTXDuaz90MEyLmyr
 ...
 }}}

 * You'll need these three Haskell files:

 {{{#!hs
 -- Foo.hs
 {-# LANGUAGE TemplateHaskell #-}
 module Foo where

 import Language.Haskell.TH

 foo :: Bool
 foo = $(conE 'True)
 }}}

 {{{#!hs
 -- Foo2.hs
 {-# LANGUAGE TemplateHaskell #-}
 module Foo2 where

 import Language.Haskell.TH

 foo2 = $(conE 'False)
 }}}

 {{{#!hs
 -- Bar.hs
 module Bar where

 import Foo
 import Foo2

 bar :: ()
 bar = foo `seq` foo2 `seq` ()
 }}}

 Once you have all of these, you can trigger the bug by invoking GHC like
 so:

 {{{
 $ ~/Software/ghc3/inplace/bin/ghc-stage2 -fforce-recomp Bar.hs -j2
 -package-id random-1.1-Gnn89iTXDuaz90MEyLmyr
 [1 of 3] Compiling Foo              ( Foo.hs, Foo.o )

 <no location info>: error:
     <command line>: can't load .so/.DLL for:
 libHSrandom-1.1-Gnn89iTXDuaz90MEyLmyr.so
 (libHSrandom-1.1-Gnn89iTXDuaz90MEyLmyr.so: cannot open shared object file:
 No such file or directory)
 [2 of 3] Compiling Foo2             ( Foo2.hs, Foo2.o )

 <no location info>: error:
     ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 8.3.20170423 for x86_64-unknown-linux):
         Dynamic linker not initialised
 CallStack (from -prof):
   Linker.CAF (<entire-module>)

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

 In case it's important, this is using 64-bit Linux.

 cc'ing angerman, who requested an easier way to reproduce this panic in
 https://ghc.haskell.org/trac/ghc/ticket/13137#comment:6.

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13607
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler