From 6302ec63fc40dd6ae1ad3003003b6b264422e8e0 Mon Sep 17 00:00:00 2001 From: Tim Peters Date: Wed, 20 Jun 2001 06:57:32 +0000 Subject: gen_iternext(): repair subtle refcount problem. NeilS, please check! This came from staring at your genbug.py, but I'm not sure it plugs all possible holes. Without this, I caught a frameobject refcount going negative, and it was also the cause (in debug build) of _Py_ForgetReference's attempt to forget an object with already- NULL _ob_prev and _ob_next pointers -- although I'm still not entirely sure how! Part of the difficulty is that frameobjects are stored on a free list that gets recycled very quickly, so if there's a stray pointer to one of them it never looks like an insane frameobject (never goes trough the free() mangling MS debug forces, etc). --- Python/ceval.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Python/ceval.c b/Python/ceval.c index cf917db..ea5c537 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -152,6 +152,11 @@ gen_iternext(genobject *gen) gen->running = 1; result = eval_frame(f); gen->running = 0; + /* The connection between this frame and its parent is over now, so + must NULL out f_back lest it get decref'ed when gen dies (note + that eval_frame sets f->f_back without bumping its refcount: we + never had a fully legit reference to it). */ + f->f_back = NULL; return result; } -- cgit v0.12