I once wrote a Smatch check based on a commit message that said we can't pass dma_alloc_coherent() pointers to virt_to_phys(). But then I never felt like I understood the rules enough to actually report the warnings as bugs. drivers/platform/x86/dcdbas.c:108 smi_data_buf_realloc() error: 'buf' came from dma_alloc_coherent() so we can't do virt_to_phys() drivers/net/caif/caif_virtio.c:414 cfv_create_genpool() error: 'cfv->alloc_addr' came from dma_alloc_coherent() so we can't do virt_to_phys() drivers/infiniband/hw/cxgb4/qp.c:135 alloc_host_sq() error: 'sq->queue' came from dma_alloc_coherent() so we can't do virt_to_phys() drivers/infiniband/hw/cxgb4/qp.c:272 create_qp() error: 'wq->rq.queue' came from dma_alloc_coherent() so we can't do virt_to_phys() drivers/infiniband/hw/cxgb4/qp.c:2628 alloc_srq_queue() error: 'wq->queue' came from dma_alloc_coherent() so we can't do virt_to_phys() drivers/infiniband/hw/ocrdma/ocrdma_verbs.c:494 ocrdma_alloc_ucontext() error: 'ctx->ah_tbl.va' came from dma_alloc_coherent() so we can't do virt_to_phys() drivers/infiniband/hw/cxgb4/qp.c 129 static int alloc_host_sq(struct c4iw_rdev *rdev, struct t4_sq *sq) 130 { 131 sq->queue = dma_alloc_coherent(&(rdev->lldi.pdev->dev), sq->memsize, 132 &(sq->dma_addr), GFP_KERNEL); 133 if (!sq->queue) 134 return -ENOMEM; 135 sq->phys_addr = virt_to_phys(sq->queue); 136 dma_unmap_addr_set(sq, mapping, sq->dma_addr); 137 return 0; 138 } Is this a bug? regards, dan carpenter