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Author neologix
Recipients ionelmc, neologix
Date 2013-08-16.12:32:05
SpamBayes Score -1.0
Marked as misclassified Yes
Message-id <>
Unfortunately, there's not much we can do about it: if dlsym() fails - which is the case here either because read() fails with EBADF, or because the file descriptor now points to another stream (i.e. not libgcc), the libc aborts (here upon pthread_exit(), not PyThread_delete_key()):
""" must be installed for pthread_cancel to work

Program received signal SIGABRT, Aborted.
[Switching to Thread 0xb7b0eb70 (LWP 17152)]
0xb7fe1424 in __kernel_vsyscall ()
(gdb) bt
#0  0xb7fe1424 in __kernel_vsyscall ()
#1  0xb7e4e941 in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2  0xb7e51d72 in *__GI_abort () at abort.c:92
#3  0xb7e8ae15 in __libc_message (do_abort=1, fmt=0xb7f606f5 "%s") at ../sysdeps/unix/sysv/linux/libc_fatal.c:189
#4  0xb7e8af44 in *__GI___libc_fatal (message=0xb7fc75ec " must be installed for pthread_cancel to work\n") at ../sysdeps/unix/sysv/linux/libc_fatal.c:200
#5  0xb7fc4ffa in pthread_cancel_init () at ../nptl/sysdeps/pthread/unwind-forcedunwind.c:65
#6  0xb7fc509d in _Unwind_ForcedUnwind (exc=0xb7b0edc0, stop=0xb7fc2bf0 <unwind_stop>, stop_argument=0xb7b0e454) at ../nptl/sysdeps/pthread/unwind-forcedunwind.c:126
#7  0xb7fc2b98 in *__GI___pthread_unwind (buf=<optimized out>) at unwind.c:130
#8  0xb7fbcce0 in __do_cancel () at pthreadP.h:265
#9  __pthread_exit (value=0x0) at pthread_exit.c:30
#10 0x08132ced in PyThread_exit_thread () at Python/thread_pthread.h:266
#11 0x08137c37 in t_bootstrap (boot_raw=0x8318aa8) at ./Modules/_threadmodule.c:1023
#12 0xb7fbbc39 in start_thread (arg=0xb7b0eb70) at pthread_create.c:304
#13 0xb7ef978e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

So if you're unlucky and end up closing the FD referring to libgcc used by dlopen/dlsym, you're pretty much screwed, and there's no way around this.

Note that you specific problem (upon PyThread_delete_key()) doesn't occur for python 2.7 because it uses and ad-hoc TLS implementation, whereas Python 3 uses the platform native TLS.
But as noted above, you can very well get an abort on pthread_exit(), and in likely many other places (pretty much everywhere libgcc can be dlopen'ed).

Unfortunately, we can't do much against this, so I'm tempted to close this as "wont fix".
Date User Action Args
2013-08-16 12:32:07neologixsetrecipients: + neologix, ionelmc
2013-08-16 12:32:07neologixsetmessageid: <>
2013-08-16 12:32:07neologixlinkissue18748 messages
2013-08-16 12:32:05neologixcreate