From patchwork Fri Oct 9 15:03:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Christian_K=C3=B6nig?= X-Patchwork-Id: 11826205 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CF277139F for ; Fri, 9 Oct 2020 15:04:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B78E522260 for ; Fri, 9 Oct 2020 15:04:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aa4N1QGk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388984AbgJIPDs (ORCPT ); Fri, 9 Oct 2020 11:03:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388803AbgJIPDr (ORCPT ); Fri, 9 Oct 2020 11:03:47 -0400 Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A72BC0613D2; Fri, 9 Oct 2020 08:03:46 -0700 (PDT) Received: by mail-ed1-x541.google.com with SMTP id l16so9688552eds.3; Fri, 09 Oct 2020 08:03:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=HfGOHdnl8P4UkAJXJm+asFhJ2S9PMVltmlEIidPYuz0=; b=aa4N1QGk9MW7oVueE84pS3IhklP/XdU7RdM9t04ujPc6+KsxPbCNzpAmnfSeiYSmsC KZHr/LYqlvTGsoZDC8fMF7aq5OM7PcEj+UFzb/n5MBMqNsV4HiFNcfPx+U870RxwOmLw GRoRXjF2T5oyi2JVye4+SIOr5LZDF+F7fqGvrZu/jXjQRTccEH+EzI3DH/xZJp/mz+yO OwWK8xhq3V2y4QsDyDIf+dMsxIEbHlQTRm4WK0p8lbBa0q8jYQfoCm/ZoqeSuAefFrVZ 0MuUPGHPEXS1TyeXAZHNNS1KCQ/ZLCrRDgD86GSjDsitEqB1cZOrUExVxuVKJacSGZqs I2BA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=HfGOHdnl8P4UkAJXJm+asFhJ2S9PMVltmlEIidPYuz0=; b=heExrcx6mH4nPlsNCo8CsxnAjrr1e/q6wGfr6J+seyDBOHDGdVy7N9Ob65Pj7txBFo nXwuXkwhjDYxI0gOCDn5J5OmaD1GdVik5CVbr60qHTQDSDRc7HkzZ2jnE7MPXRUKKhuc xkR7u5b+YktKOg0X6WLyzJWi577CiYTGBc9JVwZdRFb6zUH/0VXBRV4TSzgQ0fgiJ58Q AsuGtFPNzUku1xmVMaqRBW7PfjHf9LkvrPXRPA9yZ9Ht0NNiZ+S0w0zYwVAoC1KxaHxJ tOMzeBVdVv3kPDoyo0hLACh/dqNXUbsYRja58dIJ1rkvU+XLzTGv9B9571+q4cOQBEUG P27w== X-Gm-Message-State: AOAM531K/vYsSKIKUcjIoXY7nUJSstTNyxAxNYuMboK+doeCTQd9lrc3 8lEap5ZZds8Da3HhomhJnDA= X-Google-Smtp-Source: ABdhPJyibPjE78lcVPlBYyG6PW0fP1GpDj3X5Tpm1VzsO7r6v4QYdB2IMOhxokvqNlnbjQNZuzUauQ== X-Received: by 2002:aa7:cc18:: with SMTP id q24mr8619083edt.108.1602255824666; Fri, 09 Oct 2020 08:03:44 -0700 (PDT) Received: from abel.fritz.box ([2a02:908:1252:fb60:65f3:51d4:50d0:15b0]) by smtp.gmail.com with ESMTPSA id v14sm789364edy.68.2020.10.09.08.03.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 08:03:43 -0700 (PDT) From: " =?utf-8?q?Christian_K=C3=B6nig?= " X-Google-Original-From: =?utf-8?q?Christian_K=C3=B6nig?= To: 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, jgg@ziepe.ca Subject: [PATCH 1/6] mm: mmap: fix fput in error path Date: Fri, 9 Oct 2020 17:03:37 +0200 Message-Id: <20201009150342.1979-1-christian.koenig@amd.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 Reviewed-by: Jason Gunthorpe --- 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 --- a/drivers/dma-buf/dma-buf.c +++ 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); - ret = dmabuf->ops->mmap(dmabuf, vma); - if (ret) { - /* restore old parameters on failure */ - vma->vm_file = oldfile; - fput(dmabuf->file); - } else { - if (oldfile) - fput(oldfile); - } - return ret; + vma->vm_file = get_file(dmabuf->file); + vma->vm_pgoff = pgoff; + return dmabuf->ops->mmap(dmabuf, vma); } EXPORT_SYMBOL_GPL(dma_buf_mmap); diff --git a/mm/mmap.c b/mm/mmap.c index 40248d84ad5f..3a2670d73355 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1852,8 +1852,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, return addr; unmap_and_free_vma: + fput(vma->vm_file); vma->vm_file = NULL; - fput(file); /* Undo any partial mapping done by a device driver. */ unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);