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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 B6295C10DCE for ; Wed, 18 Mar 2020 11:01:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 76B4F2076F for ; Wed, 18 Mar 2020 11:01:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584529272; bh=M8URaHMyLbOAuXYgTHwd0O8zOnmlQoi9wjYDbhAlz30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=0GSEoT+WAhldJGLv6hAN+CrI75wCdBv8BTX//Ge+XaVoJ31jcgu27MA0s/QmN4qwU noUtyK06pN72jGrjUT0tgvyDf6QJ6+/gfdoK0oplkOmTq1dkXr9lfw/oFzbIKhsWkT KmQZIBMzQcGE1raV2LKQlBwYNdO/C3ur5TINh08I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727415AbgCRLBL (ORCPT ); Wed, 18 Mar 2020 07:01:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:47588 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726550AbgCRLBL (ORCPT ); Wed, 18 Mar 2020 07:01:11 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6B8B42076D; Wed, 18 Mar 2020 11:01:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584529270; bh=M8URaHMyLbOAuXYgTHwd0O8zOnmlQoi9wjYDbhAlz30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QwvR6OpwEeUWcjwMeYQZiyEmBLKi4CCnoeD3n0R/6HoPfpigLoZRIw5RA0jLBnorN XTdG5fo+Kjy8ETKhQZuZzuhgchcq9iPlf9NVcbCXFCIL5jeOTrcWRL2LCr3i4Qcs/s gN/OnsWSidwGOuiNMzDFmNgZv9qXNN4B1wiQlstw= Date: Wed, 18 Mar 2020 12:01:08 +0100 From: Greg Kroah-Hartman To: Xiyu Yang Cc: Arnd Bergmann , Vishnu DASA , Xin Tan , Allison Randal , Thomas Gleixner , linux-kernel@vger.kernel.org, yuanxzhang@fudan.edu.cn, kjlu@umn.edu Subject: Re: [PATCH] VMCI: Fix potential NULL pointer dereference when acquire a lock Message-ID: <20200318110108.GA2305113@kroah.com> References: <1584376610-11979-1-git-send-email-xiyuyang19@fudan.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1584376610-11979-1-git-send-email-xiyuyang19@fudan.edu.cn> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 17, 2020 at 12:36:47AM +0800, Xiyu Yang wrote: > A NULL pointer can be returned by vmci_ctx_get(). Thus add a > corresponding check so that a NULL pointer dereference will > be avoided when acquire a lock in spin_lock. > > Signed-off-by: Xiyu Yang > Signed-off-by: Xin Tan > --- > drivers/misc/vmw_vmci/vmci_context.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/misc/vmw_vmci/vmci_context.c b/drivers/misc/vmw_vmci/vmci_context.c > index 16695366ec92..a20878fba374 100644 > --- a/drivers/misc/vmw_vmci/vmci_context.c > +++ b/drivers/misc/vmw_vmci/vmci_context.c > @@ -898,6 +898,8 @@ void vmci_ctx_rcv_notifications_release(u32 context_id, > bool success) > { > struct vmci_ctx *context = vmci_ctx_get(context_id); > + if (context == NULL) > + return; But, if you look at the code, context_id is guaranteed to point to a valid context, right? Or can this somehow get dropped between the last "get" and this one? Anyway, the coding style is wrong here, always run checkpatch.pl on your patches please. thanks, greg k-h