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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 45112C433DF for ; Fri, 9 Oct 2020 15:15:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0AE26222E9 for ; Fri, 9 Oct 2020 15:15:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="fiL8LqVI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389213AbgJIPPo (ORCPT ); Fri, 9 Oct 2020 11:15:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388533AbgJIPPn (ORCPT ); Fri, 9 Oct 2020 11:15:43 -0400 Received: from mail-qt1-x843.google.com (mail-qt1-x843.google.com [IPv6:2607:f8b0:4864:20::843]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F0C2C0613D2 for ; Fri, 9 Oct 2020 08:15:42 -0700 (PDT) Received: by mail-qt1-x843.google.com with SMTP id g3so8159394qtq.10 for ; Fri, 09 Oct 2020 08:15:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=XeahOZa88YOWCvFbh6+bgMvAS5KgvoSIrQZEwsz1AvI=; b=fiL8LqVIzi0BjC3AqpEniGWmtrH2e79DZDkKidQOoBdeBwwAF9glihw+P1udtUiRiR dTk+zv6qfOMRvAe+t3ZpstOPjWPwltaqd/54uMwnhyMbGimWYP6wjQZSPDPRSBLDMEq3 jODLb9NnENznI2EjlVY8eeeQyOUt4wDCUBVw5E4o4CtxhrkZCvZljgQal96XAy815jPH RDf/kD1jB8E0S7A8xBT0hfridv/3aaapdFgFp0DMdGUAYVCsNNXdo32vpE1si8aOY0qD 6JQLnOXMhIaPxpkffwZ3sgo12yyxh9cXcLPNx5AWVvptt5wn10sWuE/osKnMQoWVJT4F EMkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=XeahOZa88YOWCvFbh6+bgMvAS5KgvoSIrQZEwsz1AvI=; b=uDbh+/W7s4A+1PsGKPKIiQeYtdqNct4CbSxzcVpjevWccanAI80sdzhsHOeZgZdAaA lBF6cnjYBzhO/I8QLS087U2g5jQW+qi4ItxnpBzymu5Go3zbIvzLthbya53JIubGFPbX tSU4ZEXp1K36bMe+z/m49JuDsSTh+QvLQXASOANdQQt3Fav/L1CENuNybN+x4XNffbDQ 9RwpRlFmNXqeHBisTkpnUAYxAGYGAygntJy3uZfPjnay33jucTG352S0DRWcQbffLKMd bRzgl/jw+yevQt23/+BxNbU/vtlEJwibFWJpO2XUmUvxRNbookJpjBB4YB5hXPeCEfLK MF8A== X-Gm-Message-State: AOAM533K0rEGJYh1mGuAmHSgPcWq2vi3xJjv1G2vqmqJDYkbnvb+SIjx gTQXEVl0HTBVcxKpFaz/PjgG2Q== X-Google-Smtp-Source: ABdhPJxmLOKDbXxWMI0YoJdQfdZgk6XHAKS3TkXBLEezFKBn9UGmtIW842jk7ARXlak9j8uix2/hmg== X-Received: by 2002:ac8:545a:: with SMTP id d26mr14359060qtq.124.1602256541398; Fri, 09 Oct 2020 08:15:41 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id s123sm6228708qkd.128.2020.10.09.08.15.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 08:15:40 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1kQu7Q-0020Yl-8k; Fri, 09 Oct 2020 12:15:40 -0300 Date: Fri, 9 Oct 2020 12:15:40 -0300 From: Jason Gunthorpe To: Christian =?utf-8?B?S8O2bmln?= Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, chris@chris-wilson.co.uk, airlied@redhat.com, akpm@linux-foundation.org, daniel@ffwll.ch, sumit.semwal@linaro.org, willy@infradead.org, jhubbard@nvidia.com Subject: Re: [PATCH 1/6] mm: mmap: fix fput in error path Message-ID: <20201009151540.GX5177@ziepe.ca> References: <20201009150342.1979-1-christian.koenig@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201009150342.1979-1-christian.koenig@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 09, 2020 at 05:03:37PM +0200, Christian König wrote: > Patch "495c10cc1c0c CHROMIUM: dma-buf: restore args..." > adds a workaround for a bug in mmap_region. > > As the comment states ->mmap() callback can change > vma->vm_file and so we might call fput() on the wrong file. > > Revert the workaround and proper fix this in mmap_region. > > Signed-off-by: Christian König > drivers/dma-buf/dma-buf.c | 22 +++++----------------- > mm/mmap.c | 2 +- > 2 files changed, 6 insertions(+), 18 deletions(-) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index a6ba4d598f0e..edd57402a48a 100644 > +++ b/drivers/dma-buf/dma-buf.c > @@ -1143,9 +1143,6 @@ EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); > int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, > unsigned long pgoff) > { > - struct file *oldfile; > - int ret; > - > if (WARN_ON(!dmabuf || !vma)) > return -EINVAL; > > @@ -1163,22 +1160,13 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, > return -EINVAL; > > /* readjust the vma */ > - get_file(dmabuf->file); > - oldfile = vma->vm_file; > - vma->vm_file = dmabuf->file; > - vma->vm_pgoff = pgoff; > + if (vma->vm_file) > + fput(vma->vm_file); This if is redundant too But otherwise Reviewed-by: Jason Gunthorpe Thanks, Jason