nvdimm: ndtest: Return -ENOMEM if devm_kcalloc() fails in ndtest_probe()

devm_kcalloc() may fail. ndtest_probe() allocates three DMA address
arrays (dcr_dma, label_dma, dimm_dma) and later unconditionally uses
them in ndtest_nvdimm_init(), which can lead to a NULL pointer
dereference under low-memory conditions.

Check all three allocations and return -ENOMEM if any allocation fails,
jumping to the common error path. Do not emit an extra error message
since the allocator already warns on allocation failure.

Fixes: 9399ab61ad82 ("ndtest: Add dimms to the two buses")
Cc: [e-mail]
Signed-off-by: Guangshuo Li <[e-mail]>
Reviewed-by: Alison Schofield <[e-mail]>
Reviewed-by: Ira Weiny <[e-mail]>
Reviewed-by: Dave Jiang <[e-mail]>
Signed-off-by: Ira Weiny <[e-mail]>

tools/testing/nvdimm/test/ndtest.c

···
 
 	p->dcr_dma = devm_kcalloc(&p->pdev.dev, NUM_DCR,
 				 sizeof(dma_addr_t), GFP_KERNEL);
+	if (!p->dcr_dma) {
+		rc = -ENOMEM;
+		goto err;
+	}
 	p->label_dma = devm_kcalloc(&p->pdev.dev, NUM_DCR,
 				   sizeof(dma_addr_t), GFP_KERNEL);
+	if (!p->label_dma) {
+		rc = -ENOMEM;
+		goto err;
+	}
 	p->dimm_dma = devm_kcalloc(&p->pdev.dev, NUM_DCR,
 				  sizeof(dma_addr_t), GFP_KERNEL);
-
+	if (!p->dimm_dma) {
+		rc = -ENOMEM;
+		goto err;
+	}
 	rc = ndtest_nvdimm_init(p);
 	if (rc)
 		goto err;