From a93810cc3d1a062bf5edbe9c14795d0360cda8a4 Mon Sep 17 00:00:00 2001
From: Alexey Naumov <alexey.naumov@gmail.com>
Date: Sun, 25 May 2014 17:10:21 +0600
Subject: [PATCH] Fix possible crash in DLL_THREAD_DETACH (explodes in .Net
 Framework)

---
 libraries/liblmdb/mdb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index f66b719..40e68de 100644
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -3677,7 +3677,9 @@ static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
 	case DLL_THREAD_DETACH:
 		for (i=0; i<mdb_tls_nkeys; i++) {
 			MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
-			mdb_env_reader_dest(r);
+			if (r) {
+				mdb_env_reader_dest(r);
+			}
 		}
 		break;
 	case DLL_PROCESS_DETACH: break;