[GHC] #7726: unexpected out of memory error on FreeBSD

26 Feb 2013

      #7726: unexpected out of memory error on FreeBSD
-------------------------------+--------------------------------------------
Reporter:  nejstastnejsistene  |          Owner:                
    Type:  bug                 |         Status:  new           
Priority:  normal              |      Component:  Runtime System
 Version:  7.4.2               |       Keywords:                
      Os:  FreeBSD             |   Architecture:  x86           
 Failure:  Runtime crash       |      Blockedby:                
Blocking:                      |        Related:                
-------------------------------+--------------------------------------------
 I wrote a daemon that periodically scrapes information from a webpage that
 crashes after about 20 hours with the error: "out of memory (requested
 1048576 bytes)". The program runs fine on my Ubuntu machine, but always
 crashes on FreeBSD even though there is plenty of memory to spare/memory
 stays constant/etc.

 I boiled it down to the following code, which consistently crashes after
 about 4000-6000 iterations when compiled with -O2, and about 35000
 without.
 {{{
 import Data.Conduit
 import Data.Conduit.List
 import qualified Data.ByteString as B
 import Network.HTTP.Conduit

 main :: IO ()
 main = do
     manager <- newManager def
     loop manager 1

 loop :: Manager -> Int -> IO ()
 loop manager i = do
     putStrLn $ show i
     request <- parseUrl "http://localhost:8000/courselist.html"
     html <- runResourceT $ do
         response <- http request manager
         fmap B.concat $ responseBody response $$+- consume
     loop manager $ i + 1
 }}}

 For debugging, I served a copy of of a typical html sample from localhost
 using "python -m SimpleHTTPServer". The html file is attached.

 Sample Output:[[BR]]
 {{{
 ...
 35361
 35362
 35363
 35364
 35365
 main: out of memory (requested 1048576 bytes)
 }}}

 Other information:
 {{{
 $ uname -a
 FreeBSD oriskova 9.1-RELEASE FreeBSD 9.1-RELEASE #0 r243826: Tue Dec  4
 06:55:39 UTC 2012
 root@obrian.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386
 }}}

 {{{
 $ gcc -v
 Using built-in specs.
 Target: i386-undermydesk-freebsd
 Configured with: FreeBSD/i386 system compiler
 Thread model: posix[[BR]]
 gcc version 4.2.1 20070831 patched [FreeBSD]
 }}}

 I wasn't sure if I should submit this or not since it seemed fairly
 specific to http-conduit, but the wiki said to go ahead and submit runtime
 errors, so that's what I did. This is my first time ever submitting a bug
 report and I tried my best to follow all the instructions at
 [http://hackage.haskell.org/trac/ghc/wiki/ReportABug], but please tell me
 if there is something I'm doing wrong.

-- 
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7726
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler