Check for integer overflow in allocate() (#9172)

Summary: Check for integer overflow in allocate() (#9172)

Test Plan: validate

Reviewers: austin

Reviewed By: austin

Subscribers: simonmar, relrod, carter

Differential Revision: https://phabricator.haskell.org/D36

1 files changed, 20 insertions, 0 deletions

diff --git a/testsuite/tests/rts/overflow2.hs b/testsuite/tests/rts/overflow2.hs
new file mode 100644
index 0000000000..ac72158f45
--- /dev/null
+++ b/testsuite/tests/rts/overflow2.hs
@@ -0,0 +1,20 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+module Main where
+
+import Foreign
+
+-- Test allocate(), the easy way.
+data Cap = Cap
+foreign import ccall "rts_unsafeGetMyCapability" myCapability :: IO (Ptr Cap)
+foreign import ccall "allocate" allocate :: Ptr Cap -> Word -> IO (Ptr ())
+
+-- Number of words n such that n * sizeof(W_) exactly overflows a word
+-- (2^30 on a 32-bit system, 2^61 on a 64-bit system)
+overflowWordCount :: Word
+overflowWordCount = fromInteger $
+                    (fromIntegral (maxBound :: Word) + 1) `div`
+                    fromIntegral (sizeOf (undefined :: Word))
+
+main = do
+  cap <- myCapability
+  allocate cap (overflowWordCount - 1)