[GHC] #780: internal error: mallocBytesRWX:

#780: internal error: mallocBytesRWX:
------------------------------------+---------------------------------------
  Reporter:  dreamer.tan@xxxxxxxxx  |          Owner:       
      Type:  bug                    |         Status:  new  
  Priority:  normal                 |      Milestone:       
 Component:  GHCi                   |        Version:  6.4.2
  Severity:  minor                  |       Keywords:       
Difficulty:  Unknown                |   Architecture:  x86  
        Os:  Linux                  |  
------------------------------------+---------------------------------------
while loading my code (RBtrees implementation) sometimes interpreter says:
 OK
 but sometimes (quite often) it crashes with description like:
 {{{
 Prelude Main> :load E.hs
 Compiling Main             ( E.hs, interpreted )
 ghc-6.4.2: internal error: mallocBytesRWX: failed to protect 0x0xa8e5c70

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

 my RBtrees implementation is not finished yet, I found out that
 interpreter
 crashes only after I add "veryLeftChild" function (code below).
 Compiler works fine with or without this function, no problems.
 my code:

 {{{
 module Main
     where

 import IO

 {- --- implementacja drzew czerwono-czarnych wg. Okasakiego
 ---------------- -}

 data Color = Red | Black
 data Tree x = E | T Color (Tree x) x (Tree x)

 type Set a = Tree a

 -- empty : T -> bool
 empty = E

 -- member : x,T -> bool
 member _ E = False
 member n@(k,x,y) (T _ l (k',_,_) r) | k < k'  = member n l
                                                                         |
 k > k'  = member n r
                                                                         |
 k == k' = True

 -- insert : x,T -> T
 insert n@(k,x,y) s = makeBlack(insert_ s)
         where
                 insert_ (T col l n'@(k',x',y') r ) | k < k'  = balance col
 (insert_ l) n' r
 | k > k'  = balance col l n' (insert_ r)
 | k == k' = T col l n r ;
                 insert_ E = T Red E n E ;
                 makeBlack (T _ l n' r) = T Black l n' r

 -- balance T -> T
 balance Black (T Red (T Red a x b) y c) z d = T Red (T Black a x b) y (T
 Black c z d)
 balance Black (T Red a x (T Red b y c)) z d = T Red (T Black a x b) y (T
 Black c z d)
 balance Black a x (T Red (T Red b y c) z d) = T Red (T Black a x b) y (T
 Black c z d)
 balance Black a x (T Red b y (T Red c z d)) = T Red (T Black a x b) y (T
 Black c z d)
 balance color a x b = T color a x b


 -- locate x,T -> T
 locate k tree@(T _ left@(T _ _ k1 _) k' right@(T _ _ k2 _)) | k == k'
 = tree
 | k1 < k && k < k2  = tree
 | k1 >= k                       = locate k left
 | k <= k2                       = locate k right

 veryLeftChild tree@(T _ left k _) | left == E   = k
                                                                   | True
 = veryLeftChild left

 -- next k tree =


 -- delete : x,T -> T
 {- remove n@(k,x,y) s = remove_ s
         where
                 remove_ -}

 {- --- main i miedzymordzie
 ------------------------------------------------ -}

 main = do
         hSetBuffering stdin LineBuffering
         n <- getLine
         while (rInt n) empty -- wywolanie operacji na drzewie (poczatkowo
 pustym)

 rInt :: String -> Int
 rInt = read

 -- scan : String -> (cmd, x, y)
 scan (l:' ':xs) = ( l, rInt x, rInt y )
         where
                 (x,y) = scan xs;
                 scan (x:xs) | x == ' ' = ([], xs)
                                         | True     = (x:xs', ys') where
 (xs',ys') = scan(xs)
                 scan [] = ([],[])

 -- while iteruje operacje i razy na tree
 while i tree = do
         if i == 0
                 then return []
                 else do
                         cmd <- getLine
                         let (output, tree') = command (scan cmd) tree
                         putStr output
                         r <- while (i-1) tree'
                         return r

 -- wywoluje odpowiednia operacje na drzewie
 command (cmd,x,y) tree | cmd == 'W' = ("", insert (x*x+y*y,x,y) tree )
                                            | cmd == 'U' = ("usun\n", tree
 )
                                            | cmd == 'D' = ("dalszy\n",
 tree )
                                            | cmd == 'B' = ("blizszy\n",
 tree )
                                            | True               = error
 "wrong command"

 }}}

 I use ghc 6.4.2, Linux, Fedora Core 5, x86. For any further info contact
 me through dreamer.tan@xxxxxxxxx

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/780>
GHC <http://www.haskell.org/ghc/>
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