From patchwork Mon Oct 12 08:52:02 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: 269714 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 A19FCC43457 for ; Mon, 12 Oct 2020 08:52:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 452F4218AC for ; Mon, 12 Oct 2020 08:52:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="lw+tUQcX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726104AbgJLIwI (ORCPT ); Mon, 12 Oct 2020 04:52:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726862AbgJLIwI (ORCPT ); Mon, 12 Oct 2020 04:52:08 -0400 Received: from mail-ej1-x643.google.com (mail-ej1-x643.google.com [IPv6:2a00:1450:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7EABC0613CE; Mon, 12 Oct 2020 01:52:06 -0700 (PDT) Received: by mail-ej1-x643.google.com with SMTP id qp15so22100698ejb.3; Mon, 12 Oct 2020 01:52:06 -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=yMIANltJzggMKevCuA/64ylJ5xrfMe99CRAziEtSDMY=; b=lw+tUQcX6E58leo0iNUqUuxVirmooB9X9E28JBa9u2lgsb0RDv0+NxJBs03bTu7r0B D5EPdSramySPYUis9ltXlotS4rQuxBR+Lpg3kMC59NVAL4HKTGbhmk92F5o8LIbmtzv7 iMpjDgh6fHILhflZmN61tUTEN+tVt4sHxRVmsmlXUWFTWigpqtu+/NNfdmgb6t9xuYQJ UR1KOZokmCcW8f1eYTtWvUlJrfmNcsSSOy5zYIB6J+97c1BT/O3HLomn+xovaPPdAKVB dQVqbzeDFYRKcQP3MlkRlIElHDn3nkr52Yh/OQIpwBDSFtHpuLbXkazdkd5l455I7zZ6 nJlw== 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=yMIANltJzggMKevCuA/64ylJ5xrfMe99CRAziEtSDMY=; b=J7wMn2rO1Nq8qg9osIos6IjZLEWJ2I+QSDhwEI9kP1Mx2IltyNF0/Oc62BjmgTMgHb h5LiuPVYBadf9Vi/9Gxun1eNPrEznNOw8E2ySnx/ZGLHChOAKzlXWCXuzN8UIPQiebLN FMV76qt6h1QWUt7KKzPeREWuEFuJGJ4vQmH9IG+vRGASj0d7ZFvFnYkKHC4sZG5Dvo1G usfypL1o4Cn464jKsQQf8vXZ6Ef/5K85DRjhXkAaPC45O6LXi4z2/CWoFDvylplb0Qr4 TRgqYWJaHkw6hNDbd6Q3H2PIobeiDJb/B/SW2iqLGNg7kS9PaGz16VV+NX3YCw7vSK0U eZoA== X-Gm-Message-State: AOAM530KJixxeJqr4LP8Nze8wh4WA7jAuwPId+Zvve4YuqCWfOKp0VbP CpjXeqvzrmKLP7CYg3mt7v4= X-Google-Smtp-Source: ABdhPJxnwEuylsU7eSmkWOtF42j8bglh0/rf5pkHlz0ZkTIK1CSAgwpiELeW85OngsabmXKbddLIWw== X-Received: by 2002:a17:906:95c5:: with SMTP id n5mr27686729ejy.111.1602492725376; Mon, 12 Oct 2020 01:52:05 -0700 (PDT) Received: from abel.fritz.box ([2a02:908:1252:fb60:6a6c:c67:2644:1d74]) by smtp.gmail.com with ESMTPSA id o35sm8622988edd.4.2020.10.12.01.52.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Oct 2020 01:52:04 -0700 (PDT) From: "=?UTF-8?q?Christian=20K=C3=B6nig?=" X-Google-Original-From: =?utf-8?q?Christian_K=C3=B6nig?= To: akpm@linux-foundation.org, 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, daniel@ffwll.ch, sumit.semwal@linaro.org, willy@infradead.org, jhubbard@nvidia.com, jgg@ziepe.ca, linmiaohe@huawei.com Subject: [PATCH 1/2] mm: mmap: fix fput in error path v2 Date: Mon, 12 Oct 2020 10:52:02 +0200 Message-Id: <20201012085203.56119-1-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. v2: drop the extra if in dma_buf_mmap as well Signed-off-by: Christian König Reviewed-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe Reviewed-by: Jason Gunthorpe --- drivers/dma-buf/dma-buf.c | 20 +++----------------- mm/mmap.c | 2 +- 2 files changed, 4 insertions(+), 18 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index a6ba4d598f0e..08630d057cf2 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 +1160,11 @@ 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; + fput(vma->vm_file); + vma->vm_file = get_file(dmabuf->file); vma->vm_pgoff = pgoff; - 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; - + 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);