On Mon, Sep 14, 2020 at 03:30:47PM +0200, Christian König wrote: > Am 14.09.20 um 15:29 schrieb Christian König: > > Hi Andrew, > > > > I'm the new DMA-buf maintainer and Daniel and others came up with > > patches extending the use of the dma_buf_mmap() function. > > > > Now this function is doing something a bit odd by changing the > > vma->vm_file while installing a VMA in the mmap() system call It doesn't look obviously safe as mmap_region() has an interesting mix of file and vma->file Eg it calls mapping_unmap_writable() using both routes What about security? Is it OK that some other random file, maybe in another process, is being linked to this mmap? > > The background here is that DMA-buf allows device drivers to > > export buffer which are then imported into another device > > driver. The mmap() handler of the importing device driver then > > find that the pgoff belongs to the exporting device and so > > redirects the mmap() call there. So the pgoff is some virtualized thing? Jason
