From 2778c999e39142b6e2f092028e0b05ef29bdb901 Mon Sep 17 00:00:00 2001 From: "Gregory P. Smith" Date: Mon, 21 Jan 2008 07:11:11 +0000 Subject: Provide a sanity check during PyThreadState_DeleteCurrent() and PyThreadState_Delete() to avoid an infinite loop when the tstate list is messed up and has somehow becomes circular and does not contain the current thread. I don't know how this happens but it does, *very* rarely. On more than one hardware platform. I have not been able to reproduce it manually. Attaching to a process where its happening: it has always been in an infinite loop over a single element tstate list that is not the tstate we're looking to delete. It has been in t_bootstrap()'s call to PyThreadState_DeleteCurrent() as a pthread is exiting. --- Python/pystate.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Python/pystate.c b/Python/pystate.c index 086789d..36b06d6 100644 --- a/Python/pystate.c +++ b/Python/pystate.c @@ -240,6 +240,7 @@ tstate_delete_common(PyThreadState *tstate) { PyInterpreterState *interp; PyThreadState **p; + PyThreadState *prev_p = NULL; if (tstate == NULL) Py_FatalError("PyThreadState_Delete: NULL tstate"); interp = tstate->interp; @@ -252,6 +253,15 @@ tstate_delete_common(PyThreadState *tstate) "PyThreadState_Delete: invalid tstate"); if (*p == tstate) break; + if (*p == prev_p) + Py_FatalError( + "PyThreadState_Delete: small circular list(!)" + " and tstate not found."); + prev_p = *p; + if ((*p)->next == interp->tstate_head) + Py_FatalError( + "PyThreadState_Delete: circular list(!) and" + " tstate not found."); } *p = tstate->next; HEAD_UNLOCK(); -- cgit v0.12