From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E31A6C07E9D for ; Thu, 29 Sep 2022 05:54:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234859AbiI2FyT (ORCPT ); Thu, 29 Sep 2022 01:54:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234847AbiI2FyR (ORCPT ); Thu, 29 Sep 2022 01:54:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6CC6E12B5FA for ; Wed, 28 Sep 2022 22:54:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 92D0B6200E for ; Thu, 29 Sep 2022 05:54:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71AB3C433D6; Thu, 29 Sep 2022 05:54:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664430855; bh=g15tzfzPdhSnHrHSTmuII/jk7Tm4dZCtS/XXnDPqtyQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tfBEw+s8MOVjo4iTJNPZPcjjYTBZAdqre9O9iVsIcJ5MhFUPxQf9ytYYxh0mkDJyq sugtZ4zKLBV/+4g1giWF0Kf1ZoZNCMcoWPFBXYcxsSlZ62bixfCUgjs++/HFJdFsC/ WKziSoaA1VpwLGc3Ohm01yN3PUBHs0Llhq+qQgwz5FQ0VOrYHdG6QGl0t74Vlj6T31 bUuv7S9pAlAviHbNPagcA2E8ppy/27XQWldqwQCY+6T0nmlRmOmLCJfqkcKtHCaThp xbArcV84t4f51azWiOjZyvvP1pGl+cO9Aa6nGKQBfW+b6kKYFJt5cAKs+0eEhoXl3B xFggI8QsBK6ZA== Date: Thu, 29 Sep 2022 08:54:10 +0300 From: Leon Romanovsky To: Dominique Martinet Cc: v9fs-developer@lists.sourceforge.net, linux_oss@crudebyte.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, syzbot+67d13108d855f451cafc@syzkaller.appspotmail.com Subject: Re: [PATCH v3] 9p: client_create/destroy: only call trans_mod->close after create Message-ID: References: <20220928215800.1749929-1-asmadeus@codewreck.org> <20220928221923.1751130-1-asmadeus@codewreck.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220928221923.1751130-1-asmadeus@codewreck.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 29, 2022 at 07:19:23AM +0900, Dominique Martinet wrote: > destroy code would incorrectly call close() if trans_mod exists after some > hasty code cleanup: we need to make sure we only call close after create > > Link: https://lkml.kernel.org/r/20220928214417.1749609-1-asmadeus@codewreck.org > Link: https://lkml.kernel.org/r/00000000000015ac7905e97ebaed@google.com > Reported-by: syzbot+67d13108d855f451cafc@syzkaller.appspotmail.com > Reported-by: Leon Romanovsky > Fixes: 3ff51294a055 ("9p: p9_client_create: use p9_client_destroy on failure") > Signed-off-by: Dominique Martinet > --- > v1->v2: also reset trans on create error > v2->v3: fix silly compile errors > > Sorry for the multiple mails, that's what I get for not even doing basic > tests before talking... Please always submit new patch versions as new one and don't reply-to. It breaks flows of everyone who relies on proper email threading. > > net/9p/client.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/net/9p/client.c b/net/9p/client.c > index bfa80f01992e..41e825a8da7c 100644 > --- a/net/9p/client.c > +++ b/net/9p/client.c > @@ -971,6 +971,7 @@ struct p9_client *p9_client_create(const char *dev_name, char *options) > spin_lock_init(&clnt->lock); > idr_init(&clnt->fids); > idr_init(&clnt->reqs); > + clnt->trans = ERR_PTR(-EINVAL); > > err = parse_opts(options, clnt); > if (err < 0) > @@ -990,8 +991,14 @@ struct p9_client *p9_client_create(const char *dev_name, char *options) > clnt, clnt->trans_mod, clnt->msize, clnt->proto_version); > > err = clnt->trans_mod->create(clnt, dev_name, options); > - if (err) > + // ensure clnt->trans is initialized to call close() on destroy > + // if and only if create succeeded Please use /* */ comment style. > + if (err < 0) { > + clnt->trans = ERR_PTR(err); > goto out; > + } > + if (IS_ERR(clnt->trans)) > + clnt->trans = NULL; > > if (clnt->msize > clnt->trans_mod->maxsize) { > clnt->msize = clnt->trans_mod->maxsize; > @@ -1036,7 +1043,7 @@ void p9_client_destroy(struct p9_client *clnt) > > p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt); > > - if (clnt->trans_mod) > + if (clnt->trans_mod && !IS_ERR(clnt->trans)) It is completely no-go to rely on internal value inside of structure after failure in ->create() callback. > clnt->trans_mod->close(clnt); > > v9fs_put_trans(clnt->trans_mod); > -- > 2.35.1 >