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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB9F9C388F9 for ; Tue, 27 Oct 2020 11:05:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 909D821655 for ; Tue, 27 Oct 2020 11:05:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QAHatsGN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2898914AbgJ0LFz (ORCPT ); Tue, 27 Oct 2020 07:05:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:41825 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2898906AbgJ0LFy (ORCPT ); Tue, 27 Oct 2020 07:05:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603796753; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FrjeCAan5jwNXoKxJoHy3Krr60faw0rldSpx6L/g/YM=; b=QAHatsGNIWsbbpQY/mVJnieTBypB02TkZxDleKxk9wi5CIxfeCaeWH1UpRNQCyjPH1Mhez 2xknsRNKLyNrjr7z/HDRXeefNeHEPaGp1+tT2bowZpXGOUGKa+iulydcMNjuVit33dBoKP 3xbg2/RRcV/EvzvztsjsVmb9TC9Gmzg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-459-Hb0IV2mzMM6PWJegTkv_9w-1; Tue, 27 Oct 2020 07:05:49 -0400 X-MC-Unique: Hb0IV2mzMM6PWJegTkv_9w-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9201D101F7A6; Tue, 27 Oct 2020 11:05:48 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-70.rdu2.redhat.com [10.10.120.70]) by smtp.corp.redhat.com (Postfix) with ESMTP id 899275D9F3; Tue, 27 Oct 2020 11:05:47 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20201021131133.128016-1-colin.king@canonical.com> References: <20201021131133.128016-1-colin.king@canonical.com> To: Colin King Cc: dhowells@redhat.com, linux-afs@lists.infradead.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][next] afs: fix a dereference on pointer cell before cell is null checked MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3189276.1603796746.1@warthog.procyon.org.uk> Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2020 11:05:46 +0000 Message-ID: <3189277.1603796746@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Colin King wrote: > @@ -606,7 +605,7 @@ void afs_unuse_cell(struct afs_net *net, struct afs_= cell *cell, enum afs_cell_tr > = > u =3D atomic_read(&cell->ref); > a =3D atomic_dec_return(&cell->active); > - trace_afs_cell(debug_id, u, a, reason); > + trace_afs_cell(cell->debug_id, u, a, reason); It's probably better to read cell->debug_id before calling atomic_dec_return(). I have a patch for this based on a report by Dan Carpenter, so no need to = send a revised patch. Thanks, David