Bugs item #1166660, was opened at 2005-03-19 21:48 Message generated for change (Comment added) made by mwh You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1166660&group_id=5470
Category: Threads Group: Platform-specific >Status: Closed >Resolution: Fixed Priority: 5 Submitted By: Yariv Ido (dcoder) Assigned to: Michael Hudson (mwh) Summary: The readline module can cause python to segfault Initial Comment: When starting an interactive interpreter in another thread, with readline's completion functionality, there exists a race condition which causes the Python interpreter to segfault. There's a small discussion about this bug at <http://www.scipy.net/roundup/ipython/issue30>. Attached is a small proof-of-concept code. Please note that some people couldn't reproduce this on slower machines. I've managed to reproduce it on several Linux systems (Dual Xeon computers), using Python 2.3.4, 2.4 and 2.4.1c2. Thanks in advance. ---------------------------------------------------------------------- >Comment By: Michael Hudson (mwh) Date: 2005-03-30 12:23 Message: Logged In: YES user_id=6656 Oh, forget all that, I had a leap in understanding about the existing threads- vs-hooks code in readline.c: it's all insane nonsense. I used the PyGILState_* API rather than your suggestion, on the very faint chance that an embedder might be calling readline() directly and thus have not be setting _PyOS_ReadlineTState. I also fixed the 'checking the return value from a hook function' while I was there, so you don't need to submit a new report for that. Modules/readline.c revision 2.83. Thanks for the report! ---------------------------------------------------------------------- Comment By: Michael Hudson (mwh) Date: 2005-03-30 11:10 Message: Logged In: YES user_id=6656 While it does seem a bit odd to call the completer function in the thread that calls set_completer and not the thread that calls readline(), I don't immediately see how this is leading to segfaults. Do you? Anyway, I can reproduce the problem, so if your fix fixes it, I'll check it in (irrespective of fixing segfaults, it just makes more sense). ---------------------------------------------------------------------- Comment By: Michael Hudson (mwh) Date: 2005-03-29 13:10 Message: Logged In: YES user_id=6656 Unless there's some reason to suspect they share a common cause (and, I don't see one) a second report is more appropriate. Also, if you understand what's going on, you can explain there :) ---------------------------------------------------------------------- Comment By: Yariv Ido (dcoder) Date: 2005-03-28 23:33 Message: Logged In: YES user_id=326689 I haven't (Completely forgot about it, after finding the main one...). Should I post a seperate bug report, or will this one do? ---------------------------------------------------------------------- Comment By: Michael Hudson (mwh) Date: 2005-03-27 21:43 Message: Logged In: YES user_id=6656 I'll take a look at this. Did you submit a bug on the set_startup_hook problem mentioned in the ipython tracker? ---------------------------------------------------------------------- Comment By: Yariv Ido (dcoder) Date: 2005-03-19 23:59 Message: Logged In: YES user_id=326689 I may be completely off track here, but shouldn't on_completion(...) (readline.c) use _PyOS_ReadlineTState instead of completer_tstate to restore the GIL? Also, in readline_until_enter_or_signal(...), shouldn't PyEval_SaveThread()'s return value be saved back to _PyOS_ReadlineTState? It seems that these patches manage to fix the above segmentation fault... ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1166660&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
