This buffer is currently allocated in hfi1_init():

	if (reinit)
		ret = init_after_reset(dd);
	else
		ret = loadtime_init(dd);
	if (ret)
		goto done;

	/* allocate dummy tail memory for all receive contexts */
	dd->rcvhdrtail_dummy_kvaddr = dma_alloc_coherent(&dd->pcidev->dev,
							 sizeof(u64),
							 &dd->rcvhdrtail_dummy_dma,
							 GFP_KERNEL);

	if (!dd->rcvhdrtail_dummy_kvaddr) {
		dd_dev_err(dd, "cannot allocate dummy tail memory\n");
		ret = -ENOMEM;
		goto done;
	}

The reinit triggered path will overwrite the old allocation and leak it.

Fix by moving the allocation to hfi1_alloc_devdata() and the deallocation
to hfi1_free_devdata().

Link: https://lore.kernel.org/r/20211129192008.101968.91302.stgit@awfm-01.cornelisnetworks.com
Cc: stable@vger.kernel.org
Fixes: 46b010d3 ("staging/rdma/hfi1: Workaround to prevent corruption during packet delivery")
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>