RE: [PATCH v2] [hv] storvsc: Payload buffer incorrectly sized for 32 bit kernels.

[KY Srinivasan]

> -----Original Message-----
> From: Cathy Avery [mailto:cavery@xxxxxxxxxx]
> Sent: Wednesday, November 23, 2016 5:47 AM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; jejb@xxxxxxxxxxxxxxxxxx;
> martin.petersen@xxxxxxxxxx
> Cc: devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> scsi@xxxxxxxxxxxxxxx
> Subject: [PATCH v2] [hv] storvsc: Payload buffer incorrectly sized for 32 bit
> kernels.
> 
> On a 32 bit kernel sizeof(void *) is not 64 bits as hv_mpb_array
> requires. Also the buffer needs to be cleared or the upper bytes
> will contain junk.
> 
> Suggested-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Signed-off-by: Cathy Avery <cavery@xxxxxxxxxx>

Thanks Cathy.

Reviewed-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> 
> ChangeLog:
> 
> v1) Initial submission
> v2) Remove memset and replace kmalloc with kzalloc.
> ---
>  drivers/scsi/storvsc_drv.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 8ccfc9e..05526b7 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1495,9 +1495,9 @@ static int storvsc_queuecommand(struct Scsi_Host
> *host, struct scsi_cmnd *scmnd)
>  	if (sg_count) {
>  		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
> 
> -			payload_sz = (sg_count * sizeof(void *) +
> +			payload_sz = (sg_count * sizeof(u64) +
>  				      sizeof(struct vmbus_packet_mpb_array));
> -			payload = kmalloc(payload_sz, GFP_ATOMIC);
> +			payload = kzalloc(payload_sz, GFP_ATOMIC);
>  			if (!payload)
>  				return SCSI_MLQUEUE_DEVICE_BUSY;
>  		}
> --
> 2.5.0