From 540a613a9ad82808c76155b3da575327b911f9aa Mon Sep 17 00:00:00 2001 From: Michael Roth Date: Mon, 5 Mar 2012 17:44:16 -0500 Subject: [PATCH 49/98] qapi: dealloc visitor, fix premature free and iteration logic Currently we do 3 things wrong: 1) The list iterator, in practice, is used in a manner where the pointer we pass in is the same as the pointer we assign the output to from visit_next_list(). This causes an infinite loop where we keep freeing the same structures. 2) We attempt to free list->value rather than list. visit_type_ handles this. We should only be concerned with the containing list. 3) We free prematurely: iterator function will continue accessing values we've already freed. This patch should fix all of these issues. QmpOutputVisitor also suffers from 1). Reviewed-by: Anthony Liguori Signed-off-by: Michael Roth Signed-off-by: Luiz Capitulino (cherry picked from commit 5666dd19dd95d966be00d0c3e7efdfaecc096ff3) Conflicts: qapi/qapi-dealloc-visitor.c Signed-off-by: Jeff Cody Signed-off-by: Michal Novotny --- qapi/qapi-dealloc-visitor.c | 20 +++++++++++++++----- 1 files changed, 15 insertions(+), 5 deletions(-) diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c index 8cde4dd..28b23c1 100644 --- a/qapi/qapi-dealloc-visitor.c +++ b/qapi/qapi-dealloc-visitor.c @@ -26,6 +26,7 @@ struct QapiDeallocVisitor { Visitor visitor; QTAILQ_HEAD(, StackEntry) stack; + bool is_list_head; }; static QapiDeallocVisitor *to_qov(Visitor *v) @@ -70,15 +71,24 @@ static void qapi_dealloc_end_struct(Visitor *v, Error **errp) static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp) { + QapiDeallocVisitor *qov = to_qov(v); + qov->is_list_head = true; } -static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **list, +static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **listp, Error **errp) { - GenericList *retval = *list; - qemu_free(retval->value); - *list = retval->next; - return retval; + GenericList *list = *listp; + QapiDeallocVisitor *qov = to_qov(v); + + if (!qov->is_list_head) { + *listp = list->next; + qemu_free(list); + return *listp; + } + + qov->is_list_head = false; + return list; } static void qapi_dealloc_end_list(Visitor *v, Error **errp) -- 1.7.7.6