Re: [PATCH v3] nvdimm: ndtest: Return -ENOMEM if devm_kcalloc() fails in ndtest_probe()

[Dave Jiang <dave.jiang@intel.com>]

On 9/24/25 11:44 PM, Guangshuo Li wrote:
> 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: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
> changelog:
> v3:
> - Add NULL checks for all three devm_kcalloc() calls and goto the common
>   error label on failure.
> 
> v2:
> - Drop pr_err() on allocation failure; only NULL-check and return -ENOMEM.
> - No other changes.
> ---
>  tools/testing/nvdimm/test/ndtest.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/nvdimm/test/ndtest.c b/tools/testing/nvdimm/test/ndtest.c
> index 68a064ce598c..8e3b6be53839 100644
> --- a/tools/testing/nvdimm/test/ndtest.c
> +++ b/tools/testing/nvdimm/test/ndtest.c
> @@ -850,11 +850,22 @@ static int ndtest_probe(struct platform_device *pdev)
>  
>  	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;