To be honest I think the if(WARN_ON(!dmabuf)) return -EINVAL handling here is misleading in the first place.

Returning -EINVAL on a hard coding error is not good practice and should probably be removed from the DMA-buf subsystem in general.

Christian.

Am 18.08.21 um 13:58 schrieb Nuno Sá:

On top of warning about a NULL object, we also want to return with a proper error code (as done in 'dma_buf_begin_cpu_access()'). Otherwise, we will get a NULL pointer dereference.

Fixes: fc13020e086b ("dma-buf: add support for kernel cpu access") Signed-off-by: Nuno Sá nuno.sa@analog.com

---

drivers/dma-buf/dma-buf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 63d32261b63f..8ec7876dd523 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1231,7 +1231,8 @@ int dma_buf_end_cpu_access(struct dma_buf *dmabuf, { int ret = 0;

• WARN_ON(!dmabuf);

• if (WARN_ON(!dmabuf))

• return -EINVAL;
  

might_lock(&dmabuf->resv->lock.base);