[Python-Dev] refleaks & test_tcl & threads (original) (raw)

Tim Peters tim.peters at gmail.com
Tue Apr 18 05:39:36 CEST 2006

[Thomas Wouters]

... One remaining issue with refleakhunting on my machine is that testtcl can't stand being run twice. Even without -R, this makes Python hang while waiting for a mutex in the second run through testtcl:

...trunk $ ./python -E -tt Lib/test/regrtest testtcl testtcl Attaching gdb to the hung process shows this unenlightening trace: _#0 0x00002b7d6629514b in lllmutexlockwait () from /lib/libpthread.so.0 #1 0x00002b7d6639a280 in completed.4801 () from /lib/libpthread.so.0 #2 0x0000000000000004 in ?? () #3 0x00002b7d66291dca in pthreadmutexlock () from /lib/libpthread.so.0 #4 0x0000000000000000 in ?? () The process has one other thread, which is stuck here: _#0 0x00002b7d667f14d6 in selectnocancel () from /lib/libc.so.6 #1 0x00002b7d67512d8c in TclWaitForEvent () from /usr/lib/libtcl8.4.so.0 #2 0x00002b7d66290b1c in startthread () from /lib/libpthread.so.0 #3 0x00002b7d667f8962 in clone () from /lib/libc.so.6 #4 0x0000000000000000 in ?? () It smells like testtcl or Tkinter is doing something wrong with regards to threads. I can reproduce this on a few machines, but all of them run newish linux kernels with newish glibc's and newish tcl/tk. At least in kernel/libc land, various thread related things changed of late. I don't have access to other machines with tcl/tk right now, but I wonder if anyone can reproduce this in different situations.

FYI, there's no problem running test_tcl with -R on WinXP Pro SP2 from current trunk:

C:\Code\python\PCbuild>python_d -E -tt ../lib/test/regrtest.py -R:: test_tcl test_tcl beginning 9 repetitions 123456789 ......... 1 test OK. [27306 refs]

That's using Tcl/Tk 8.4.12 (I don't know what newish means in Tcl-land these days).

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