Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:88942
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain zend.com designates 209.85.223.176 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <CABBJUpdyraZS_VEsF-tRdEF4cMsoQw=BRCWuFc-YqFJzGFD57g@mail.gmail.com>
References: <alpine.DEB.2.20.1510201531060.10651@whisky.home.derickrethans.nl>
	<CABBJUpeTDADC+hp+W--j0=WTcpV4o3HCw+fOoZjZhnj3oB3eGg@mail.gmail.com>
	<BLU436-SMTP6829FBC1B9AC709F51F6A1E2390@phx.gbl>
	<alpine.DEB.2.20.1510201707000.10651@whisky.home.derickrethans.nl>
	<BLU436-SMTP145497E730AEEA90A90C695E2390@phx.gbl>
	<alpine.DEB.2.20.1510211536470.10651@whisky.home.derickrethans.nl>
	<CABBJUpdyraZS_VEsF-tRdEF4cMsoQw=BRCWuFc-YqFJzGFD57g@mail.gmail.com>
Date: Mon, 26 Oct 2015 15:11:00 +0300
Message-ID: <CA+9eiLsw0bXZ8UnMkTjXfKDb4o-9knrQf7QaUcc24=AqGzL17Q@mail.gmail.com>
To: Xinchen Hui <laruence@php.net>
Cc: Derick Rethans <derick@php.net>, Bob Weinand <bobwei9@hotmail.com>, 
	PHP Developers Mailing List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a113f910ac30726052300dab5
Subject: Re: [PHP-DEV] Issues with exceptions and overloading opcodes
From: dmitry@zend.com (Dmitry Stogov)

--001a113f910ac30726052300dab5
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Hi,

I'm going to re-fix the problem with the following patch:

https://gist.github.com/dstogov/1eb77a9f2ff7dd807dd1

Thanks. Dmitry.

On Thu, Oct 22, 2015 at 5:43 AM, Xinchen Hui <laruence@php.net> wrote:

> Hey:
>
>
>
> On Wed, Oct 21, 2015 at 10:38 PM, Derick Rethans <derick@php.net> wrote:
>
>> On Tue, 20 Oct 2015, Bob Weinand wrote:
>>
>> > > Am 20.10.2015 um 18:08 schrieb Derick Rethans <derick@php.net>:
>> > >
>> > > On Tue, 20 Oct 2015, Bob Weinand wrote:
>> > >
>> > >>> Am 20.10.2015 um 17:11 schrieb Xinchen Hui <laruence@php.net>:
>> > >>>
>> > >>> On Tue, Oct 20, 2015 at 10:45 PM, Derick Rethans <derick@php.net
>> <mailto:derick@php.net>> wrote:
>> > >>>
>> > >>>> When hacking on Xdebug for PHP 7, I ran into some issues where
>> > >>>> PHP would just spin around. This happens when there is an
>> > >>>> exception, and I use overloaded opcodes. I wrote a small example
>> > >>>> extension at
>> > >>>> https://github.com/derickr/php-minimal-opcode-overloading-example
>> > >>>> with a test case (
>> > >>>>
>> https://github.com/derickr/php-minimal-opcode-overloading-example/blob/m=
aster/tests/test.php
>> > >>>> ) that shows that something is looping in executing opcodes, as
>> > >>>> the HANDLE_EXCEPTION iirc doesn't advance to the next opline. I
>> > >>>> believe this is a recent enough change, as it only started
>> > >>>> happening after I upgraded from about RC1 to latest master.
>> > >>>>
>> > >>>> Would you care to have a look?
>> > >>>>
>> > >>> This is introduced by a fix made by Bob,
>> > >>> https://github.com/php/php-src/commit/808f62bb
>> > >>> <https://github.com/php/php-src/commit/808f62bb>
>> > >>>
>> > >>> Bob, I am going to revert this for now, since you didn't include a
>> > >>> test script to show where the problem was, I am not sure why you
>> > >>> made this?
>> > >>
>> > >> I didn't add any test case as we don't have any APIs in php-src
>> > >> using that user_opcode handler. I discussed the change back then
>> > >> with Dmitry and committed with his review.
>> > >>
>> > >> It concretely broke uopz which might throw an exception itself. And
>> > >> in turn we realized that for integrity we need to ensure that
>> > >> opline =3D=3D EX(opline) else we'll end up with different behavior =
in
>> > >> global register builds and normal builds.
>> > >>
>> > >> In general, you should not overload ZEND_HANDLE_EXCEPTION (if you
>> > >> need to, have a special handling for it, but never directly
>> > >> dispatch to it). It is quite special being the only opcode actually
>> > >> allowing EG(exception) to be non-NULL at the start of it.
>> > >>
>> > >> You are doing an #ifdef ZTS to exempt it=E2=80=A6 why don't you alw=
ays
>> > >> exempt it?
>> > >
>> > > Even if I do (like I've just pushed into the extension), the test
>> > > still fails because the code loops. So you did break something.
>> >
>> > Ah, ZEND_CATCH indeed also allows EG(exception) to be non-null=E2=80=
=A6
>> >
>> > =E2=80=A6 maybe I should write
>> >
>> > if (EG(exception)
>> >  && opline->opcode !=3D ZEND_HANDLE_EXCEPTION && opline->opcode !=3D
>> ZEND_CATCH
>> >  && ret !=3D ZEND_USER_OPCODE_DISPATCH && ret !=3D ZEND_USER_OPCODE_RE=
TURN
>> && ret !=3D ZEND_USER_OPCODE_ENTER && ret !=3D ZEND_USER_OPCODE_LEAVE) {
>> >     HANDLE_EXCEPTION();
>> > }
>> >
>> > to allow dispatching for these two opcodes too?
>>
>> I don't know. Dmitry, Xinchen? I'd like to get this resolved soon..
>>
>> The commit which cause this problem has been reverted,  so this is
> resolved , and regarding the problem which is commit tried to fixed, we
> will find a better way to re-fix that.
>
> thanks
>
>> cheers,
>> Derick
>
>
>
>
> --
> Xinchen Hui
> @Laruence
> http://www.laruence.com/
>

--001a113f910ac30726052300dab5--