internal error: mallocBytesRWX:

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@gmail.com

Trac metadata

Trac field	Value
Version	6.4.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	GHCi
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