From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49587) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKKHi-0004LJ-AH for qemu-devel@nongnu.org; Tue, 05 Jul 2016 02:56:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bKKHe-00031t-Vq for qemu-devel@nongnu.org; Tue, 05 Jul 2016 02:56:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59390) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKKHe-00031l-Pt for qemu-devel@nongnu.org; Tue, 05 Jul 2016 02:56:38 -0400 Date: Tue, 5 Jul 2016 14:56:35 +0800 From: Fam Zheng Message-ID: <20160705065635.GA29307@ad.usersys.redhat.com> References: <1467636059-12557-1-git-send-email-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1467636059-12557-1-git-send-email-pbonzini@redhat.com> Subject: Re: [Qemu-devel] [PATCH] json-streamer: fix double-free on exiting during a parse List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, xiecl.fnst@cn.fujitsu.com, armbru@redhat.com On Mon, 07/04 14:40, Paolo Bonzini wrote: > Now that json-streamer tries not to leak tokens on incomplete parse, > the tokens can be freed twice if QEMU destroys the json-streamer > object during the parser->emit call. To fix this, create the new > empty GQueue earlier, so that it is already in place when the old > one is passed to parser->emit. > > Reported-by: Changlong Xie > Signed-off-by: Paolo Bonzini Two meta questions: Is there a reproducer and/or test case coverage? Does qemu-stable need this? Fam > --- > qobject/json-streamer.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c > index 7164390..c51c202 100644 > --- a/qobject/json-streamer.c > +++ b/qobject/json-streamer.c > @@ -39,6 +39,7 @@ static void json_message_process_token(JSONLexer *lexer, GString *input, > { > JSONMessageParser *parser = container_of(lexer, JSONMessageParser, lexer); > JSONToken *token; > + GQueue *tokens; > > switch (type) { > case JSON_LCURLY: > @@ -96,9 +97,12 @@ out_emit: > /* send current list of tokens to parser and reset tokenizer */ > parser->brace_count = 0; > parser->bracket_count = 0; > - /* parser->emit takes ownership of parser->tokens. */ > - parser->emit(parser, parser->tokens); > + /* parser->emit takes ownership of parser->tokens. Remove our own > + * reference to parser->tokens before handing it out to parser->emit. > + */ > + tokens = parser->tokens; > parser->tokens = g_queue_new(); > + parser->emit(parser, tokens); > parser->token_size = 0; > } > > -- > 1.8.3.1 > >