Re: [PATCH] scsi: lpfc: Fix a possible null pointer dereference

[Bart Van Assche <bvanassche@acm.org>]

On 4/2/24 6:40 PM, Huai-Yuan Liu wrote:
> In function lpfc_xcvr_data_show, the memory allocation with kmalloc might
> fail, thereby making rdp_context a null pointer. In the following context
> and functions that use this pointer, there are dereferencing operations,
> leading to null pointer dereference.
> 
> To fix this issue, a null pointer check should be added. If it is null,
> write error message and jump to 'out_free_rdp'.
> 
> Fixes: 479b0917e447 ("scsi: lpfc: Create a sysfs entry called lpfc_xcvr_data for transceiver info")
> Signed-off-by: Huai-Yuan Liu <qq810974084@gmail.com>
> ---
>   drivers/scsi/lpfc/lpfc_attr.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
> index b1c9107d3408..b11e5114b7f2 100644
> --- a/drivers/scsi/lpfc/lpfc_attr.c
> +++ b/drivers/scsi/lpfc/lpfc_attr.c
> @@ -1904,6 +1904,11 @@ lpfc_xcvr_data_show(struct device *dev, struct device_attribute *attr,
>   
>   	/* Get transceiver information */
>   	rdp_context = kmalloc(sizeof(*rdp_context), GFP_KERNEL);
> +	if (!rdp_context) {
> +		len = scnprintf(buf, PAGE_SIZE - len,
> +				"ERROR: Not enough memory\n");
> +		goto out_free_rdp;
> +	}
>   

Has this patch been verified with checkpatch? Checkpatch should have
reported the following for the above patch:

   Possible unnecessary 'out of memory' message

Thanks,

Bart.