#3514: mallocPlainForeignPtrBytes -1000 gives runtime internal error:
allocGroup:
requested zero blocks
--------------------------+-------------------------------------------------
Reporter: andrewbirkett | Owner:
Type: bug | Status: new
Priority: normal | Component: Runtime System
Version: 6.10.4 | Severity: minor
Keywords: | Testcase:
Os: Linux | Architecture: x86
--------------------------+-------------------------------------------------
Passing negative numbers to mallocPlainForeignPtrBytes causes the
following to appear:
{{{
Test: internal error: allocGroup: requested zero blocks
(GHC version 6.10.4 for i386_unknown_linux)
Please report this as a GHC bug:
http://www.haskell.org/ghc/reportabug
Aborted
}}}
Originally, a bug in my app meant that I called Data.ByteString.hGet with
a negative 'numBytes' argument, however I've managed to boil it down to a
one line test case involving just mallocPlainForeignPtrBytes as follows:
{{{
$ cat Test.hs
import GHC.ForeignPtr (mallocPlainForeignPtrBytes)
main = mallocPlainForeignPtrBytes (-1000)
$ ghc --make Test.hs
[1 of 1] Compiling Main ( Test.hs, Test.o )
Linking Test ...
$ ./Test
Test: internal error: allocGroup: requested zero blocks
(GHC version 6.10.4 for i386_unknown_linux)
Please report this as a GHC bug:
http://www.haskell.org/ghc/reportabug
Aborted
}}}
The magnitude of the number appears to have some effect; with ghc 6.10.1
it seemed to reliably crash with numBytes <= -9. But when I upgraded to
ghc 6.10.4, the test case started working. However, changing to -1000
reliably causes a crash on my box - perhaps the behaviour depends on heap
layout. Either way, the function should probably behave more gracefully
.. perhaps raising an exception.
Full gory details of my setup (ie. ghc -v output, gcc version) are
attached because they messed up the formatting.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3514>
GHC <http://www.haskell.org/ghc/>
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