Crash in event_free() on windows
Issue #1
resolved
Debugging the crash of the tests\11-gc-cycles.phpt it turned out that the following will cause crash
$t = Event::timer(new EventBase(), function () { }); $t->free();
Even ommiting the explicit freeing it'd crash in event_object_free_storage() as that's using the same snippet. Actually it looks very odd, as the pointer itself is the same in both Event::timer() when created and later when passing to event_free() ... Looking at the code of event_free() itself i can imagine that's an issue of the libevent itself, namely a locking issue in event_del(). Cant prove it yet though.
And that's why i've decided to created a ticket here and ask for assistance. Ruslan, maybe you've an idea where I should dig further?
When I look at the related libevent ext, there's no event_free() call, the event seems to be not passed for freeing to the libevent. So it might be leaked if there's no gc in the libevent itself. Anyway ommiting event_free() could solve that crash on windows.
Thanks.
Comments (12)
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repo owner
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reporter
We don't work with VS2013, that's the issue. It's even not added to the config scripts. For 5.5 it's VS2012, for earlier VS2008.
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reporter
btw. libevent can be found here http://windows.php.net/downloads/pecl/deps/
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repo owner
Oh, Should I install VS2012?
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reporter
Yep, VS2012 will for 5.5 will be probably the easiest, as the SDK there isn't separated like in VS2008. I'll be testing on VS2008 then anyway. There's a wiki page about it https://wiki.php.net/internals/windows/stepbystepbuild . VS2013 will be added somewhen soon to master only, i presume.
Btw. great you've decided to setup on windows. As you're much deeper into libevent yet than me :)
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repo owner
Once again I tried to compile PHP x86 under Windows 7 x86_64. Still no luck. Unfortunately, I lack experience in Windows programming. Last time I worked on Windows was five years ago.
The following is output from "VS2012 x86 Native Tools Command Prompt":
c:\php-sdk\phpdev\vc11\x86\src>configure --disable-all --enable-cli --enable-so kets --with-event=C:\Users\Ruslan\src\libevent-2.0.21-stable\ --disable-zts Saving configure options to config.nice.bat Checking for cl.exe ... <in default path> Detected compiler MSVC11 (Visual C++ 2012) Detected 32-bit compiler Checking for link.exe ... C:\Program Files (x86)\Microsoft Visual Studio 11.0\ C\bin\ Checking for nmake.exe ... <in default path> Checking for lib.exe ... <in default path> Checking for bison.exe ... <in default path> Checking for re2c.exe ... <in default path> Detected re2c version 0.13.5 Checking for zip.exe ... <in default path> Checking for lemon.exe ... <not found> Checking for mc.exe ... <not found> Checking for mt.exe ... <not found> Build dir: Release PHP Core: php5.dll and php5.lib Checking for wspiapi.h ... <not found> Checking for wspiapi.h ... <not found> Enabling SAPI sapi\cli Enabling extension ext\date Enabling extension ext\ereg Enabling extension ext\pcre Enabling extension ext\reflection Checking for library ws2_32.lib ... <not found> WARNING: sockets not enabled; libraries and headers not found Enabling extension ext\spl Checking for timelib_config.h ... ext/date/lib Enabling extension ext\standard Checking for event2/event.h ... <in default path> Checking for library libevent.lib ... ..\..\..\..\..\Users\Ruslan\src\libevent- .0.21-stable\libevent.lib Checking for library libevent_core.lib ... ..\..\..\..\..\Users\Ruslan\src\libe ent-2.0.21-stable\libevent_core.lib Checking for library libevent_extras.lib ... ..\..\..\..\..\Users\Ruslan\src\li event-2.0.21-stable\libevent_extras.lib Checking for pthread.h ... C:\Users\Ruslan\src\libevent-2.0.21-stable\ Checking for sched.h ... C:\Users\Ruslan\src\libevent-2.0.21-stable\ Checking for library pthreadVC2.lib ... <in LIB path> pthreadVC2.lib Checking for common.h ... ext\event\src Checking for http.h ... <in default path> Checking for php_event.h ... ext\event Enabling extension ext\event [shared] Creating build dirs... Generating files... Generating Makefile Generating main/internal_functions.c [content unchanged; skipping] Generating main/config.w32.h Generating phpize Done. Enabled extensions: ----------------------- | Extension | Mode | ----------------------- | date | static | | ereg | static | | event | shared | | pcre | static | | reflection | static | | spl | static | | standard | static | ----------------------- Enabled SAPI: ------------- | Sapi Name | ------------- | cli | ------------- -------------------------------------------- | | | -------------------------------------------- | Build type | Release | | Thread Safety | No | | Compiler | MSVC11 (Visual C++ 2012) | | Architecture | x86 | -------------------------------------------- Type 'nmake' to build PHP c:\php-sdk\phpdev\vc11\x86\src>nmake Microsoft (R) Program Maintenance Utility Version 11.00.50727.1 Copyright (C) Microsoft Corporation. All rights reserved. Recreating build dirs type ext\pcre\php_pcre.def > Release\php5.dll.def "" -h win32\ -r Release\ -x Release\ win32\build\wsyslog.mc '-h' is not recognized as an internal or external command, operable program or batch file. NMAKE : fatal error U1077: '"' : return code '0x1' Stop. c:\php-sdk\phpdev\vc11\x86\src> c:\php-sdk\phpdev\vc11\x86\src>configure --disable-all --enable-cli --enable-so kets --with-event=C:\Users\Ruslan\src\libevent-2.0.21-stable\ --disable-zts Saving configure options to config.nice.bat Checking for cl.exe ... <in default path> Detected compiler MSVC11 (Visual C++ 2012) Detected 32-bit compiler Checking for link.exe ... C:\Program Files (x86)\Microsoft Visual Studio 11.0\ C\bin\ Checking for nmake.exe ... <in default path> Checking for lib.exe ... <in default path> Checking for bison.exe ... <in default path> Checking for re2c.exe ... <in default path> Detected re2c version 0.13.5 Checking for zip.exe ... <in default path> Checking for lemon.exe ... <not found> Checking for mc.exe ... <not found> Checking for mt.exe ... <not found> Build dir: Release PHP Core: php5.dll and php5.lib Checking for wspiapi.h ... <not found> Checking for wspiapi.h ... <not found> Enabling SAPI sapi\cli Enabling extension ext\date Enabling extension ext\ereg Enabling extension ext\pcre Enabling extension ext\reflection Checking for library ws2_32.lib ... <not found> WARNING: sockets not enabled; libraries and headers not found Enabling extension ext\spl Checking for timelib_config.h ... ext/date/lib Enabling extension ext\standard Checking for event2/event.h ... <in default path> Checking for library libevent.lib ... ..\..\..\..\..\Users\Ruslan\src\libevent- .0.21-stable\libevent.lib Checking for library libevent_core.lib ... ..\..\..\..\..\Users\Ruslan\src\libe ent-2.0.21-stable\libevent_core.lib Checking for library libevent_extras.lib ... ..\..\..\..\..\Users\Ruslan\src\li event-2.0.21-stable\libevent_extras.lib Checking for pthread.h ... C:\Users\Ruslan\src\libevent-2.0.21-stable\ Checking for sched.h ... C:\Users\Ruslan\src\libevent-2.0.21-stable\ Checking for library pthreadVC2.lib ... <in LIB path> pthreadVC2.lib Checking for common.h ... ext\event\src Checking for http.h ... <in default path> Checking for php_event.h ... ext\event Enabling extension ext\event [shared] Creating build dirs... Generating files... Generating Makefile Generating main/internal_functions.c [content unchanged; skipping] Generating main/config.w32.h Generating phpize Done. Enabled extensions: ----------------------- | Extension | Mode | ----------------------- | date | static | | ereg | static | | event | shared | | pcre | static | | reflection | static | | spl | static | | standard | static | ----------------------- Enabled SAPI: ------------- | Sapi Name | ------------- | cli | ------------- -------------------------------------------- | | | -------------------------------------------- | Build type | Release | | Thread Safety | No | | Compiler | MSVC11 (Visual C++ 2012) | | Architecture | x86 | -------------------------------------------- Type 'nmake' to build PHP c:\php-sdk\phpdev\vc11\x86\src>nmake Microsoft (R) Program Maintenance Utility Version 11.00.50727.1 Copyright (C) Microsoft Corporation. All rights reserved. Recreating build dirs type ext\pcre\php_pcre.def > Release\php5.dll.def "" -h win32\ -r Release\ -x Release\ win32\build\wsyslog.mc '-h' is not recognized as an internal or external command, operable program or batch file. NMAKE : fatal error U1077: '"' : return code '0x1' Stop. c:\php-sdk\phpdev\vc11\x86\src> c:\php-sdk\phpdev\vc11\x86\src>echo %LIB% C:\Users\Ruslan\src\pthreads\Pre-built.2\lib\x86;%LIB% c:\php-sdk\phpdev\vc11\x86\src>echo %PATH% C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\Wind owsPowerShell\v1.0\;"C:\Program Files (x86)\GnuWin32\bin\";C:\Program Files\Micr osoft SQL Server\110\Tools\Binn\;C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\;C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE;;c: \php-sdk\bin\\..\bin;c:\php-sdk\bin\;D:\apps\svn\bin c:\php-sdk\phpdev\vc11\x86\src>echo %INCLUDE% ext\event\classes;C:\Users\Ruslan\src\libevent-2.0.21-stable\include;%INCLUDE% c:\php-sdk\phpdev\vc11\x86\src> -
reporter
Looks very odd, the environment seems to be broken. That's already to see in config
Checking for library ws2_32.lib ... <not found> WARNING: sockets not enabled; libraries and headers not found
the ws2_32.lib is the basic one, so it should be available.
Or with nmake
"" -h win32\ -r Release\ -x Release\ win32\build\wsyslog.mc
that should look like
"C:\Program Files (x86)\Windows Kits\8.0\bin\x86\mc.exe" -h win32\ -r Debug_TS\ -x Debug_TS\ win32\build\wsyslog.mc
Sure you use the native command promt as in wiki?
Another thing - i almost use --with-extra-libs and --with-extra-includes instead of setting the the path in the --with-* option. Multiple paths there can be separated with semicolon. For now at least, --with-event=shared should be used, as that's only the case which matters.
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repo owner
Well, I've finally set it up. I had to rebuild it all for x64.
The crash is caused by early base destruction. The code
$t = Event::timer(new EventBase(), function () { }); $t->free();doesn't cause a crash on Linux, however; at least on my amd64 Gentoo box.
The following code shouldn't crash on Windows, too:
$b = new EventBase(); $t = Event::timer($b, function () { }); $t->free();Currently I have troubles getting debug info.. One day I'll fix it )
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repo owner
Ehh, Remi has pushed some fixes, so I should package release ASAP. But this bug haunts me. I should fix it some way :) Maybe just restrict all EventBase arguments to be passed by reference? So we'll avoid getting refcount = 1.
We talked about implementing custom reference counting for EventBase objects with krakjoe in the IRC. He suggested to make a linked list for our own "GC"... I can scrcely imagine that thing, because I don't know how to properly avoid class object's auto destruction. We certainly can make full copies including underlying "struct event_base"... but it's weird.
So maybe we should just force EventBase arguments to be passed as reference variables?
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reporter
Hi,
if it works, why not. Is this already commited, so i could trigger a snapshot?
BTW, as you confirm the crash comes from the libevent, I think it would make pretty much sense to report this issue to them.
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repo owner
- changed status to resolved
Forced passing EventBase arguments by reference. All tests passed on my Windows Home Premium x64. I think we can try to make a snap.
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reporter
ups, looks like i was too slowly and you've pushed the release already and it's built, so no snapshot needed now :)
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I'm trying to set up build environment on Windows virtual machine. Struggling with weird behaviour of the configure script:
I'll continue digging into the painful Windows stuff when I find some free time again.