I got a crash running Tcl/Tk trunk (9.1b1) and tcltls 2.0.1, on linux x84_64, OpenSSL 3.0.13

While I couldn't write a short script to repro, the setup is as follow:

• tkcon runs a script from a modified version of jabberlib from the coccinella project.
• the script connects to the tclers's chat using tls (tested with both tls::socket at port 5223 and tls::import at port 5222).
• after successful connection, Tk is loaded in the interpreter with [package require Tk].
• type [exit]

The process segfaults at exit.

The relevant lines from the backtrace are (tcltls built with --enable-symbols)

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff30ee500 in BIO_ctrl () from /lib/x86_64-linux-gnu/libcrypto.so.3
(gdb) bt
#0  0x00007ffff30ee500 in BIO_ctrl () at /lib/x86_64-linux-gnu/libcrypto.so.3
#1  0x00007ffff3d79369 in ??? () at /lib/x86_64-linux-gnu/libssl.so.3
#2  0x00007ffff30ee502 in BIO_ctrl () at /lib/x86_64-linux-gnu/libcrypto.so.3
#3  0x00007ffff5e5d812 in TlsCloseProc ()
    at /usr/local/lib/tcltls2.0.1/libtcl9tls2.0.1.so
#4  0x00007ffff7cff7b4 in TclFinalizeIOSubsystem ()
    at /usr/local/lib/libtcl9.1.so
#5  0x00007ffff7cd0344 in FinalizeThread () at /usr/local/lib/libtcl9.1.so
#6  0x00007ffff7cd10f3 in Tcl_Exit () at /usr/local/lib/libtcl9.1.so
#7  0x00007ffff7c6ba01 in Tcl_ExitObjCmd () at /usr/local/lib/libtcl9.1.so
#8  0x00007ffff7c5090a in TclNRRunCallbacks () at /usr/local/lib/libtcl9.1.so

Steve Landers runs an analysis using Claude Opus 5 and it found these issues: TclTLS crash - the problem, TclTLS crash - the fix, TclLS crash - verification.

Effectively, removing Tcl_CreateExitHandler() from generic/tls.c fixes the issue.

Thanks for the report. AI sure is getting good now. I didn’t know about channels being closed after the exit handler runs. Sounds like a TCL issue too. I’ll get this fixed in the next few days. Thanks.

This issue is fixed in trunk now. Rather than remove the Tcl_CreateExitHandler call, I made it a no-op so I can use it in the future.