diff --git a/dlls/ntoskrnl.exe/ntoskrnl.c b/dlls/ntoskrnl.exe/ntoskrnl.c
index 4dd6bb38b3d..f53434aedf8 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.c
+++ b/dlls/ntoskrnl.exe/ntoskrnl.c
@@ -721,10 +721,7 @@ static NTSTATUS dispatch_ioctl( struct dispatch_context *context )
             context->in_buff = out_buff;
         }
         else
-        {
             out_buff = context->in_buff;
-            out_size = context->in_size;
-        }
     }
 
     irp = IoBuildDeviceIoControlRequest( context->params.ioctl.code, device, context->in_buff,
diff --git a/dlls/ntoskrnl.exe/tests/driver.c b/dlls/ntoskrnl.exe/tests/driver.c
index 0506011ce56..67f22a4b2b0 100644
--- a/dlls/ntoskrnl.exe/tests/driver.c
+++ b/dlls/ntoskrnl.exe/tests/driver.c
@@ -1777,17 +1777,14 @@ static NTSTATUS main_test(DEVICE_OBJECT *device, IRP *irp, IO_STACK_LOCATION *st
 
 static NTSTATUS test_basic_ioctl(IRP *irp, IO_STACK_LOCATION *stack, ULONG_PTR *info)
 {
-    ULONG length = stack->Parameters.DeviceIoControl.OutputBufferLength;
+    ULONG length = min(stack->Parameters.DeviceIoControl.OutputBufferLength, sizeof(teststr));
     char *buffer = irp->AssociatedIrp.SystemBuffer;
 
     if (!buffer)
         return STATUS_ACCESS_VIOLATION;
 
-    if (length < sizeof(teststr))
-        return STATUS_BUFFER_TOO_SMALL;
-
-    memcpy(buffer, teststr, sizeof(teststr));
-    *info = sizeof(teststr);
+    memcpy(buffer, teststr, length);
+    *info = length;
 
     return STATUS_SUCCESS;
 }
diff --git a/dlls/ntoskrnl.exe/tests/ntoskrnl.c b/dlls/ntoskrnl.exe/tests/ntoskrnl.c
index eb58878cec4..76bcf0d0ce6 100644
--- a/dlls/ntoskrnl.exe/tests/ntoskrnl.c
+++ b/dlls/ntoskrnl.exe/tests/ntoskrnl.c
@@ -190,8 +190,8 @@ static void main_test(void)
 
 static void test_basic_ioctl(void)
 {
+    char inbuf[64], buf[32];
     DWORD written;
-    char buf[32];
     BOOL res;
 
     res = DeviceIoControl(device, IOCTL_WINETEST_BASIC_IOCTL, NULL, 0, buf,
@@ -199,6 +199,13 @@ static void test_basic_ioctl(void)
     ok(res, "DeviceIoControl failed: %u\n", GetLastError());
     ok(written == sizeof(teststr), "got size %d\n", written);
     ok(!strcmp(buf, teststr), "got '%s'\n", buf);
+
+    memset(buf, 0, sizeof(buf));
+    res = DeviceIoControl(device, IOCTL_WINETEST_BASIC_IOCTL, inbuf,
+            sizeof(inbuf), buf, 10, &written, NULL);
+    ok(res, "DeviceIoControl failed: %u\n", GetLastError());
+    ok(written == 10, "got size %d\n", written);
+    ok(!strcmp(buf, "Wine is no"), "got '%s'\n", buf);
 }
 
 static void test_overlapped(void)