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Date: Thu, 12 Mar 2015 01:59:26 +0300
Message-ID: <CA+9eiLtreo5XemiyED789-Nq3FCsPw+ydDY18ntL2ueCcJEDzQ@mail.gmail.com>
To: Stanislav Malyshev <smalyshev@gmail.com>
Cc: Rasmus Lerdorf <rasmus@lerdorf.com>, Nikita Popov <nikita.ppv@gmail.com>, 
	Xinchen Hui <xinchen.h@zend.com>, Anatol Belski <ab@php.net>, PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=bcaec52be9bf188ee905110b3832
Subject: Re: [PHP-DEV] Safe execution timeout handling
From: dmitry@zend.com (Dmitry Stogov)

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On Thu, Mar 12, 2015 at 1:46 AM, Stanislav Malyshev <smalyshev@gmail.com>
wrote:

> Hi!
>
> > I think, after "max_execution_time" is exceeded, we may start another
> > "hard_timeout", and in case the EG(vm_interrupt) wasn't handled
> > "safely", kill the process.
>
> I remember such proposal floating on the list recently, with two-stage
> timeouts. But wouldn't killing the process run the same risk that it
> left something messed up in SHM?
>

yes :(
if we try to recovery from some inconsistent state we most probably crash.
I even don't talk about memory and resource leaks.


> Also, in threaded environments that's probably not an option, and PHP
> may not even own the thread.
>

I'm not sure how the existing setjmp/longjmp based timeout handling works
in ZTS environment now, because except of SHM it may also easily corrupt
the process memory shared with other threads.

Thanks. Dmitry.



>
> --
> Stas Malyshev
> smalyshev@gmail.com
>

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