On Thu, 16 Sep 2004 16:31:30 +0300 (IDT) Stanislav Malyshev <[EMAIL PROTECTED]> wrote:
> AD>>> class tables are already cleaned, etc.) - so it crashes. > AD>> > AD>>Looks like you're right, but why others can't reproduce this > AD>segfault? > > Only idea I have they didn't run it in debug mode. In the debug mode, > destroyed memory is overwritten, in the release mode it isn't. So on > debug, use-after-free cases drop dead instantly, while on release mode > they may very well work in some cases. Ok, I got it. > AD>>Sounds nice: we should not call destructors after they were > AD>>already called =) > > The problem is that if one of the dtors fails, others aren't called. > THis is OK (i.e., this is better than the alternatives), but it > confuses the engine later on the way of shutdown. Surely I agree. > AD>>I could propose a simple solution: add a global flag, which will > AD>indicate>that shutdown_destructors() was called, and do appropriate > AD>check in>zend_objects_store_del_ref(). > AD>>Comments/objections? > > I personally don't like the idea of having yet another hack flag. > Moveover, the del_ref is not the only place one may call destructors. > What I'd do is: if one of the dtors bails out, we catch it in > call_dtors and then mark all the objects as "already destroyed" - so > there's no way any dtor could be called after that from any place. > This is a bit slower performance-wise, bnut I'm not sure performance > is much of concern in situation where the code has failed in shutdown > - I don't know any "fast failure" benchmarks ;) After all, it will be > not much longer than the regular shutdown anyway - one pass over the > store. The advantage of this approach is that it follows the existing > protocol and not insterts another flag (read - branch in any function > working along the protocol) which leads to potential breakage. Sounds quite nice. Will look at it later a bit. -- Wbr, Antony Dovgal aka tony2001 [EMAIL PROTECTED] || [EMAIL PROTECTED] -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
