diff --git a/libraries/base/changelog.md b/libraries/base/changelog.md
index 5d3af3ff34e0371a51e2effa9c8716b730d72e40..2f77e41d730210822e00b6fed865cd160036c0be 100644
--- a/libraries/base/changelog.md
+++ b/libraries/base/changelog.md
@@ -28,6 +28,7 @@
      and [CLC proposal #258](https://github.com/haskell/core-libraries-committee/issues/258))
   * Add `System.Mem.performMajorGC` ([CLC proposal #230](https://github.com/haskell/core-libraries-committee/issues/230))
   * Fix exponent overflow/underflow bugs in the `Read` instances for `Float` and `Double` ([CLC proposal #192](https://github.com/haskell/core-libraries-committee/issues/192))
+  * `Foreign.C.Error.errnoToIOError` now uses the reentrant `strerror_r` to render system errors when possible ([CLC proposal #249](https://github.com/haskell/core-libraries-committee/issues/249))
   * Implement `many` and `some` methods of `instance Alternative (Compose f g)` explicitly. ([CLC proposal #181](https://github.com/haskell/core-libraries-committee/issues/181))
   * Change the types of the `GHC.Stack.StackEntry.closureType` and `GHC.InfoProv.InfoProv.ipDesc` record fields to use `GHC.Exts.Heap.ClosureType` rather than an `Int`.
     To recover the old value use `fromEnum`. ([CLC proposal #210](https://github.com/haskell/core-libraries-committee/issues/210))
diff --git a/libraries/ghc-internal/cbits/strerror.c b/libraries/ghc-internal/cbits/strerror.c
new file mode 100644
index 0000000000000000000000000000000000000000..1640a4957e795d7431d8f8f2e13f157ad04c1066
--- /dev/null
+++ b/libraries/ghc-internal/cbits/strerror.c
@@ -0,0 +1,29 @@
+// glibc will only expose the POSIX strerror_r if this is defined.
+#define _POSIX_C_SOURCE 200112L
+
+#include <string.h>
+#include <errno.h>
+
+// This must be included after <string.h> lest _GNU_SOURCE may be defined.
+#include "HsBaseConfig.h"
+
+// returns zero on success
+int base_strerror_r(int errnum, char *ptr, size_t buflen)
+{
+#if defined(HAVE_STRERROR_R)
+    int ret = strerror_r(errnum, ptr, buflen);
+    if (ret == ERANGE) {
+        // Ellipsize the error
+        ptr[buflen-4] = '.';
+        ptr[buflen-3] = '.';
+        ptr[buflen-2] = '.';
+        ret = 0;
+    }
+    return ret;
+#elif defined(HAVE_STRERROR_S)
+    strerror_s(ptr, buflen, errnum);
+    return 0;
+#else
+#error neither strerror_r nor strerror_s are supported
+#endif
+}
diff --git a/libraries/ghc-internal/configure.ac b/libraries/ghc-internal/configure.ac
index f5befee878eda43f9041cc988ddcf603005a5fd1..4eda0cd9d7b0692939dac4fbe6ca17636d9731a8 100644
--- a/libraries/ghc-internal/configure.ac
+++ b/libraries/ghc-internal/configure.ac
@@ -41,6 +41,12 @@ AC_CHECK_DECLS([CLOCK_PROCESS_CPUTIME_ID], [], [], [[#include <time.h>]])
 AC_CHECK_FUNCS([getclock getrusage times])
 AC_CHECK_FUNCS([_chsize_s ftruncate])
 
+AC_CHECK_FUNCS([strerror_r strerror_s])
+
+if test "$ac_cv_func_strerror_r" = no && test "$ac_cv_func_strerror_s" = no; then
+  AC_MSG_ERROR([Either strerror_r or strerror_s must be available])
+fi
+
 # event-related fun
 # The line below already defines HAVE_KQUEUE and HAVE_POLL, so technically some of the
 # subsequent portions that redefine them could be skipped. However, we keep those portions
diff --git a/libraries/ghc-internal/ghc-internal.cabal b/libraries/ghc-internal/ghc-internal.cabal
index 66933abdb6a57c6109c1d4197b295403d065866f..8113659953c22ef2027759e12b5d055f1c90834c 100644
--- a/libraries/ghc-internal/ghc-internal.cabal
+++ b/libraries/ghc-internal/ghc-internal.cabal
@@ -330,6 +330,7 @@ Library
           cbits/primFloat.c
           cbits/sysconf.c
           cbits/fs.c
+          cbits/strerror.c
 
       cmm-sources:
           cbits/StackCloningDecoding.cmm
diff --git a/libraries/ghc-internal/jsbits/errno.js b/libraries/ghc-internal/jsbits/errno.js
index b7ea1fb9ae01610d8f862908e28d6feaae3e2b2a..ff31029baaa5f15e84c28776eba6685fa6d9279f 100644
--- a/libraries/ghc-internal/jsbits/errno.js
+++ b/libraries/ghc-internal/jsbits/errno.js
@@ -22,7 +22,7 @@ function h$unsupported(status, c) {
     return status;
 }
 
-function h$strerror(err) {
+function h$base_strerror(err) {
     if(err === 12456) {
 	RETURN_UBX_TUP2(h$encodeUtf8("operation unsupported on this platform"), 0);
     }
diff --git a/libraries/ghc-internal/src/GHC/Internal/Foreign/C/Error.hs b/libraries/ghc-internal/src/GHC/Internal/Foreign/C/Error.hs
index 169841758b9c3d7c1b61cc9e30e4fe81dbc88b7e..103531d824674f4f285a9c579e310c9af1d8807f 100644
--- a/libraries/ghc-internal/src/GHC/Internal/Foreign/C/Error.hs
+++ b/libraries/ghc-internal/src/GHC/Internal/Foreign/C/Error.hs
@@ -91,6 +91,9 @@ module GHC.Internal.Foreign.C.Error (
 #include "HsBaseConfig.h"
 
 import GHC.Internal.Foreign.Ptr
+#if !defined(javascript_HOST_ARCH)
+import GHC.Internal.Foreign.Marshal.Alloc
+#endif
 import GHC.Internal.Foreign.C.Types
 import GHC.Internal.Foreign.C.String
 import GHC.Internal.Data.Functor            ( void )
@@ -460,6 +463,29 @@ throwErrnoPathIfMinus1_  = throwErrnoPathIf_ (== -1)
 -- conversion of an "errno" value into IO error
 -- --------------------------------------------
 
+errnoToString :: Errno -> IO String
+
+#if defined(javascript_HOST_ARCH)
+foreign import ccall unsafe "base_strerror"
+    c_strerror :: Errno -> IO (Ptr CChar)
+
+errnoToString errno = c_strerror errno >>= peekCString
+
+#else
+foreign import ccall "base_strerror_r"
+    c_strerror_r :: Errno -> Ptr CChar -> CSize -> IO CInt
+
+errnoToString errno =
+    allocaBytes len $ \ptr -> do
+        ret <- c_strerror_r errno ptr len
+        if ret /= 0
+          then return "errnoToString failed"
+          else peekCString ptr
+  where
+    len :: Num a => a
+    len = 512
+#endif
+
 -- | Construct an 'IOError' based on the given 'Errno' value.
 -- The optional information can be used to improve the accuracy of
 -- error messages.
@@ -470,7 +496,7 @@ errnoToIOError  :: String       -- ^ the location where the error occurred
                 -> Maybe String -- ^ optional filename associated with the error
                 -> IOError
 errnoToIOError loc errno maybeHdl maybeName = unsafePerformIO $ do
-    str <- strerror errno >>= peekCString
+    str <- errnoToString errno
     return (IOError maybeHdl errType loc str (Just errno') maybeName)
     where
     Errno errno' = errno
@@ -576,5 +602,3 @@ errnoToIOError loc errno maybeHdl maybeName = unsafePerformIO $ do
         | errno == eXDEV           = UnsupportedOperation
         | otherwise                = OtherError
 
-foreign import ccall unsafe "string.h" strerror :: Errno -> IO (Ptr CChar)
-