diff options
| author | Mike Pall <mike> | 2012-10-21 19:15:03 +0200 |
|---|---|---|
| committer | Mike Pall <mike> | 2012-10-21 19:17:14 +0200 |
| commit | 1d5c2ce4e295562daddfe6ce8e470749f0d42542 (patch) | |
| tree | e56ef2c9b51a466654548bb52a0ebaf7f9cb6e3d /doc | |
| parent | f6536c6696deca9fb7b9744573406c83f0f893a4 (diff) | |
| download | luajit2-1d5c2ce4e295562daddfe6ce8e470749f0d42542.tar.gz | |
Replace error with PANIC for callbacks from JIT-compiled code.
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/ext_ffi_semantics.html | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/doc/ext_ffi_semantics.html b/doc/ext_ffi_semantics.html index f8da1e60..ab02f2b8 100644 --- a/doc/ext_ffi_semantics.html +++ b/doc/ext_ffi_semantics.html @@ -934,6 +934,22 @@ advisable in general. Do this only if you know the C function, that called the callback, copes with the forced stack unwinding and doesn't leak resources. </p> +<p> +One thing that's not allowed, is to let an FFI call into a C function +get JIT-compiled, which in turn calls a callback, calling into Lua again. +Usually this attempt is caught by the interpreter first and the +C function is blacklisted for compilation. +</p> +<p> +However, this heuristic may fail under specific circumstances: e.g. a +message polling function might not run Lua callbacks right away and the call +gets JIT-compiled. If it later happens to call back into Lua, you'll get a +VM PANIC with the message <tt>"bad callback"</tt>. Then you'll need to +manually turn off JIT-compilation with +<a href="ext_jit.html#jit_onoff_func"><tt>jit.off()</tt></a> for the +surrounding Lua function that invokes such a message polling function (or +similar). +</p> <h3 id="callback_resources">Callback resource handling</h3> <p> |