| msg73649 - (view) |
Author: Hirokazu Yamamoto (ocean-city) *  |
Date: 2008-09-23 16:55 |
| I'm not sure this is python's bug or cygwin's bug, thread enabled python crashes thread related tests on cygwin. (ex: test_exit on test_sys.py, test_threading.py etc) After some investigation, I found following workaround solves this crash. Index: Modules/_ssl.c =================================================================== --- Modules/_ssl.c (revision 66562) +++ Modules/_ssl.c (working copy) @@ -1580,7 +1580,7 @@ /* Init OpenSSL */ SSL_load_error_strings(); -#ifdef WITH_THREAD +#if defined(WITH_THREAD) && !defined(__CYGWIN__) /* note that this will start threading if not already started */ if (!_setup_ssl_threads()) { return; So I applied following patch. (after reverted above workaround) Index: Modules/_ssl.c =================================================================== --- Modules/_ssl.c (revision 66562) +++ Modules/_ssl.c (working copy) @@ -1517,6 +1517,8 @@ lock. They can be useful for debugging. */ + printf("-------> %d (%u) %s %d: %ul\n", n, mode & CRYPTO_LOCK, file, line, PyThread_get_thread_ident()); + if ((_ssl_locks == NULL) | |
(n < 0) |
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| msg73650 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-09-23 16:57 |
| releast25-maint is fine probably because CRYPTO_set_locking_callback() is not used in Modules/_ssl.c. I don't try configure --with-threads on py3k, but probably same on trunk. |
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| msg73879 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-09-26 19:11 |
| >Thread 7282896l tries to lock same object twice. This was not cause of problem. I saw crash after one lock on another thread. I could create the C code to reproduce crash. (reproduce.zip) But strangely, I couldn't crash main.exe if it was built with http://www.openssl.org/source/openssl-0.9.8h.tar.gz (same version) I compiled openssl with "config -dCygwin" and "make". (I needed to fix one broken link in Include dir though) |
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| msg73886 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) * |
Date: 2008-09-26 20:59 |
| So it is a "Vendor OS problem", python is not involved. |
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| msg73895 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-09-26 21:49 |
| Sorry, I noticed another bit. If main.exe is linked to libssl.dll.a and libcrypto.dll.a it will crash, but linked to libssl.a and libcrypto.a it won't crash. (I renamed *.dll.a temporary) I'll try to build http://www.openssl.org/source/openssl-0.9.8h.tar.gz with shared mode if possible. >So it is a "Vendor OS problem", python is not involved. Yes, possibly. Because other platform is not crashing on buildbot. |
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| msg73901 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) * |
Date: 2008-09-26 22:27 |
| I think I have a beginning of an explanation: libssl.dll implements a DllMain function, whose DLL_THREAD_DETACH event calls ERR_remove_state. At this time, the (posix) thread function has already exited; pthread::exit() was already called the pthread object has been deleted. And the same (win32) thread will call sem_wait()... and maybe access freed resources. Linking against the static library does not have this problem. |
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| msg73904 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-09-26 23:04 |
| Thank you for great explanation! Probably you are right... I'll look into the code. |
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| msg73905 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-09-26 23:36 |
| Maybe I can fix this openssl bug with pthread_cleanup_push, but this is openssl bug, we cannot fix it directly. I propose to commit workaround in for 2.6 release. |
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| msg73906 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-09-26 23:52 |
| And after openssl will be fixed, change it to #if defined(WITH_THREAD) && !(defined(__CYGWIN__) && OPENSSL_VERSION_NUMBER < ???) |
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| msg73919 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-09-27 03:44 |
| That workaround leaves unused function warning. This patch is revised patch. |
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| msg76079 - (view) |
Author: Roumen Petrov (rpetrov) * |
Date: 2008-11-19 23:29 |
| I'm not sure that reported issue is openssl bug. Just tested a GCC(mingw) build of test case reproduce.zip with openssl(0.9.8i) and "pthreads-w32". The test run without problems on nt5.1(xp). |
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| msg76086 - (view) |
Author: Amaury Forgeot d'Arc (amaury.forgeotdarc) * |
Date: 2008-11-20 01:17 |
| With cygwin, calling sem_wait() in the DLL_THREAD_DETACH section of a DllMain function can crash the program. See attached zip file, it contains two C files which only include pthread.h and semaphore.h (no python, no openssl). The resulting program crashes ~30% of the time. If this pattern (in dll.c) is not allowed, it's a problem in the openssl code. If it is allowed, it's a bug in cygwin's threads implementation. We should really move this discussion to cygwin. This is no more a python issue. |
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| msg76090 - (view) |
Author: Hirokazu Yamamoto (ocean-city) * |
Date: 2008-11-20 06:04 |
| OK, I'll close this entry, and I'll post message to cygwin ml about this issue. # I already posted it to openssl-dev, but there was no response. http://www.nabble.com/Bug%3A-crash-on-cygwin-if-uses-CRYPTO_set_locking_callback-and-shared-library-to19699111.html#a19712690 |
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