From: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx> [ 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. And, in the vm_fault handler, use vmf_insert_pfn to share the page's pfn to userspace instead of directly sharing the page (via struct page *). Link: https://lkml.kernel.org/r/20240624063952.1572359-6-vivek.kasireddy@xxxxxxxxx Signed-off-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx> Suggested-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Dave Airlie <airlied@xxxxxxxxxx> Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Peter Xu <peterx@xxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxx> Cc: Dongwon Kim <dongwon.kim@xxxxxxxxx> Cc: Junxiao Chang <junxiao.chang@xxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Reported-by: syzbot+3d218f7b6c5511a83a79@xxxxxxxxxxxxxxxxxxxxxxxxx [ 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@xxxxxxxxx> --- drivers/dma-buf/udmabuf.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 2bcdb935a3ac..e57d57a10bb0 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -33,12 +33,13 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) struct vm_area_struct *vma = vmf->vma; struct udmabuf *ubuf = vma->vm_private_data; pgoff_t pgoff = vmf->pgoff; + unsigned long pfn; if (pgoff >= ubuf->pagecount) return VM_FAULT_SIGBUS; - vmf->page = ubuf->pages[pgoff]; - get_page(vmf->page); - return 0; + + pfn = page_to_pfn(ubuf->pages[pgoff]); + return vmf_insert_pfn(vma, vmf->address, pfn); } static const struct vm_operations_struct udmabuf_vm_ops = { @@ -54,6 +55,7 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma) vma->vm_ops = &udmabuf_vm_ops; vma->vm_private_data = ubuf; + vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; return 0; } -- 2.30.2
