From: "Christian König" <ckoenig.leichtzumerken@gmail.com>
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 [thread overview]
Message-ID: <20201009150342.1979-1-christian.koenig@amd.com> (raw)
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 <christian.koenig@amd.com>
---
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);
--
2.17.1
next reply other threads:[~2020-10-09 15:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 15:03 Christian König [this message]
2020-10-09 15:03 ` [PATCH 2/6] mm: introduce vma_set_file function v3 Christian König
2020-10-09 15:14 ` Jason Gunthorpe
2020-10-12 8:11 ` Christian König
2020-10-09 15:03 ` [PATCH 3/6] drm/radeon: stop using pages with drm_prime_sg_to_page_addr_arrays Christian König
2020-10-09 15:03 ` [PATCH 4/6] drm/amdgpu: " Christian König
2020-10-09 15:03 ` [PATCH 5/6] drm/nouveau: " Christian König
2020-10-09 15:03 ` [PATCH 6/6] drm/prime: document that use the page array is deprecated v2 Christian König
2020-10-09 16:24 ` Daniel Vetter
2020-10-09 16:27 ` Daniel Vetter
2020-10-09 15:15 ` [PATCH 1/6] mm: mmap: fix fput in error path Jason Gunthorpe
2020-10-09 22:04 ` Andrew Morton
2020-10-09 22:25 ` Jason Gunthorpe
2020-10-12 8:13 ` Christian König
2020-10-10 1:48 linmiaohe
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