[Python-bugs-list] [ python-Bugs-814726 ] RedHat 9 blows up at dlclose of pyexpat.so

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Bugs item #814726, was opened at 2003-09-30 06:55
Message generated for change (Comment added) made by anthonybaxter
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Category: Extension Modules
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: benson margulies (benson_basis)
Assigned to: Nobody/Anonymous (nobody)
Summary: RedHat 9 blows up at dlclose of pyexpat.so

Initial Comment:
With python 2.3, built with GCC 3.2.



With RedHat 9.0 ... glibc-2.3.2-27.9



With python linked into the application as a shared 

library...



a SIGSEGV at exit. Perhaps the modules should be 

marked -z nodelete to duck this latest incarnation of an 

old familiar glibc bug?



atexit:



(gdb) where

#0  0x42073771 in free () from /lib/tls/libc.so.6

#1  0x420ebd8e in __unregister_atfork () 

from /lib/tls/libc.so.6

#2  0x42029fb8 in __cxa_finalize () 

from /lib/tls/libc.so.6

#3  0x41fd19fc in __do_global_dtors_aux () 

from /vobs/rex/bin_g/RH72-gcc-3.2/python/pyexpat.so

#4  0x41fef3a9 in _fini () from /vobs/rex/bin_g/RH72-

gcc-3.2/python/pyexpat.so

#5  0x4000ce44 in _dl_fini () from /lib/ld-linux.so.2

#6  0x42029d40 in exit () from /lib/tls/libc.so.6

#7  0x42015708 in __libc_start_main () 

from /lib/tls/libc.so.6



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>Comment By: Anthony Baxter (anthonybaxter)
Date: 2003-10-04 10:26

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configure --without-cxx 

is the magic you probably want.



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Comment By: benson margulies (benson_basis)
Date: 2003-10-04 00:15

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I didn't realize that the decision to use g++ as the linker was 

one that we made here locally (I didn't do the build). We'll try 

avoiding it and see if things get better.



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Comment By: Martin v. Löwis (loewis)
Date: 2003-10-04 00:14

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I did not suggest to avoid gcc, but to avoid g++ (I'm only

guessing here, since you haven't reported the build log, ldd

output for pyexpat.so, or similar - but it might be that

pyexpat.so was linked with g++, which would explain that it

somehow calls __cxa_finalize).



pyexpat itself has no C++ in it.

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Comment By: benson margulies (benson_basis)
Date: 2003-10-03 23:37

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If this is a system bug, it's a glibc bug, not a gcc bug. So 

avoiding gcc won't help. RedHat/glibc have a very bad track 

record of exploding when dlclosing C++ shared libraries. 

They've had many bugs of this form. If pyexpat has to have 

C++ code, it should be coded with no static constructor 

usage to avoid this problem, and similiar problems that might 

arise other places. TLS isn't in action.

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Comment By: Martin v. Löwis (loewis)
Date: 2003-10-03 23:33

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This sounds like a bug in the system to me, not a bug in Python.



Maybe it can be worked-around by not building Python with g++?



Maybe it can be worked-around by not using buggy TLS

implementations?

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