Re: [PATCH v5.4-v6.1] udmabuf: use vmf_insert_pfn and VM_PFNMAP for handling mmap

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

The upstream commit SHA1 provided is correct: 7d79cd784470395539bda91bf0b3505ff5b2ab6d

WARNING: Author mismatch between patch and upstream commit:
Backport author: Andrey Kalachev <kalachev@swemel.ru>
Commit author: Vivek Kasireddy <vivek.kasireddy@intel.com>


Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.11.y | Present (exact SHA1)
6.6.y | Not found
6.1.y | Not found

Note: The patch differs from the upstream commit:
---
1:  7d79cd7844703 ! 1:  14a0c0b74cf0d udmabuf: use vmf_insert_pfn and VM_PFNMAP for handling mmap
    @@ Metadata
      ## Commit message ##
         udmabuf: use vmf_insert_pfn and VM_PFNMAP for handling mmap
     
    +    [ Upstream commit 7d79cd784470395539bda91bf0b3505ff5b2ab6d ]
    +
         Add VM_PFNMAP to vm_flags in the mmap handler to ensure that the mappings
         would be managed without using struct page.
     
    @@ Commit message
         Cc: Oscar Salvador <osalvador@suse.de>
         Cc: Shuah Khan <shuah@kernel.org>
         Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    +    Reported-by: syzbot+3d218f7b6c5511a83a79@syzkaller.appspotmail.com
    +    [ Andrey: Backport required minor change: replace call
    +    to vm_flags_set() in mmap_udmabuf() by direct
    +    modification of the vma->vm_flags, because the set
    +    of vm_flags_*() functions is not in this versions. ]
    +    Signed-off-by: Andrey Kalachev <kalachev@swemel.ru>
     
      ## drivers/dma-buf/udmabuf.c ##
     @@ drivers/dma-buf/udmabuf.c: static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf)
    @@ drivers/dma-buf/udmabuf.c: static int mmap_udmabuf(struct dma_buf *buf, struct v
      
      	vma->vm_ops = &udmabuf_vm_ops;
      	vma->vm_private_data = ubuf;
    -+	vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
    ++	vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
      	return 0;
      }
      
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |
| stable/linux-5.4.y        |  Success    |  Success   |