Re: [PATCH v2 3/3] scsi: sd: Fix interpretation of VPD B9h length

From: Hannes Reinecke <hare@suse.de>
To: Tyler Erickson <tyler.erickson@seagate.com>,
	damien.lemoal@opensource.wdc.com, jejb@linux.ibm.com,
	martin.petersen@oracle.com
Cc: linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org,
	muhammad.ahmad@seagate.com, stable@vger.kernel.org
Subject: Re: [PATCH v2 3/3] scsi: sd: Fix interpretation of VPD B9h length
Date: Fri, 3 Jun 2022 08:18:40 +0200	[thread overview]
Message-ID: <94c1c9ae-67cb-2491-0f00-477d78178616@suse.de> (raw)
In-Reply-To: <20220602225113.10218-4-tyler.erickson@seagate.com>

On 6/3/22 00:51, Tyler Erickson wrote:
> Fixing the interpretation of the length of the B9h VPD page
> (concurrent positioning ranges). Adding 4 is necessary as
> the first 4 bytes of the page is the header with page number
> and length information. Adding 3 was likely a misinterpretation
> of the SBC-5 specification which sets all offsets starting at zero.
> 
> This fixes the error in dmesg:
> [ 9.014456] sd 1:0:0:0: [sda] Invalid Concurrent Positioning Ranges VPD page
> 
> Cc: stable@vger.kernel.org
> Fixes: e815d36548f0 ("scsi: sd: add concurrent positioning ranges support")
> Signed-off-by: Tyler Erickson <tyler.erickson@seagate.com>
> Reviewed-by: Muhammad Ahmad <muhammad.ahmad@seagate.com>
> Tested-by: Michael English <michael.english@seagate.com>
> ---
>   drivers/scsi/sd.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 749316462075..f25b0cc5dd21 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -3072,7 +3072,7 @@ static void sd_read_cpr(struct scsi_disk *sdkp)
>   		goto out;
>   
>   	/* We must have at least a 64B header and one 32B range descriptor */
> -	vpd_len = get_unaligned_be16(&buffer[2]) + 3;
> +	vpd_len = get_unaligned_be16(&buffer[2]) + 4;
>   	if (vpd_len > buf_len || vpd_len < 64 + 32 || (vpd_len & 31)) {
>   		sd_printk(KERN_ERR, sdkp,
>   			  "Invalid Concurrent Positioning Ranges VPD page\n");

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
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