On Tue, Aug 11, 2026 at 1:41 PM T.J. Mercier tjmercier@google.com wrote:
Write permissions on the /dev/dma_heap/* device files are not required to issue ioctls and allocate dmabufs. Applications should be opening these file as O_RDONLY. The BPF dmabuf_iter selftest already does this. [1]
Users are pointing to these selftests as examples of how use dmabuf, and encountering permission errors on systems where write permissions are not available on /dev/dma_heap/*. Apply the principle of least privilege to selftests which open dmabuf heaps by removing the write access mode and using O_RDONLY for the open() instead.
The same is true for the vgem test using /dev/dri/card.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tool...
Signed-off-by: T.J. Mercier tjmercier@google.com
Acked-by: John Stultz jstultz@google.com
thanks -john