[LU-19496] Check result of dma_map_sgtable before dereferencing transaction

• Type: Bug
• Resolution: Fixed
• Priority: Medium
• Fix Version/s: Lustre 2.17.0
• Severity: 3
• Assignee: Chris Horn
• Reporter: Chris Horn

Description

	if (tn->tn_gpu) {
		rc = lnet_rdma_map_sg_attrs(dev->device, tn->tn_sgt.sgl,
					    sg_count, tn->tn_dmadir);
		if (rc > 0)
			tn->tn_sgt.nents = rc;
	} else {
		rc = dma_map_sgtable(dev->device, &tn->tn_sgt, tn->tn_dmadir,
				     0);
	}

	tn->tn_sgt_mapped = true;

	/* tn_num_iovec used for convenience in some debug messages */
	tn->tn_num_iovec = tn->tn_sgt.nents;

The return value of dma_map_sgtable() is not checked for errors. If this call fails, tn->tn_sgt_mapped will still be set to true, which may cause resource leaks or undefined behavior later.