From: Mark Lord <kernel@start.ca>
To: Dan Carpenter <dan.carpenter@oracle.com>, Mark Lord <mlord@pobox.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: [report] sata_qstor.c: ancient pointer math bug
Date: Wed, 2 Mar 2016 09:30:40 -0500 [thread overview]
Message-ID: <56D6F910.7000300@start.ca> (raw)
In-Reply-To: <20160302094458.GA5213@mwanda>
On 16-03-02 04:44 AM, Dan Carpenter wrote:
..
> drivers/ata/sata_qstor.c
> 252 static unsigned int qs_fill_sg(struct ata_queued_cmd *qc)
> 253 {
> 254 struct scatterlist *sg;
> 255 struct ata_port *ap = qc->ap;
> 256 struct qs_port_priv *pp = ap->private_data;
> 257 u8 *prd = pp->pkt + QS_CPB_BYTES;
> 258 unsigned int si;
> 259
> 260 for_each_sg(qc->sg, sg, qc->n_elem, si) {
> 261 u64 addr;
> 262 u32 len;
> 263
> 264 addr = sg_dma_address(sg);
> 265 *(__le64 *)prd = cpu_to_le64(addr);
> 266 prd += sizeof(u64);
> 267
> 268 len = sg_dma_len(sg);
> 269 *(__le32 *)prd = cpu_to_le32(len);
> 270 prd += sizeof(u64);
>
> This is almost certainly a cut and paste bug where prd += sizeof(u32)
> was intended. Probably no one cares at this point though...
No, the hardware really does want sizeof(u64) in both places above.
A PRD entry is 16 bytes in total.
--
Mark Lord
Real-Time Remedies Inc.
mlord@pobox.com
prev parent reply other threads:[~2016-03-02 14:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 9:44 [report] sata_qstor.c: ancient pointer math bug Dan Carpenter
2016-03-02 14:28 ` Mark Lord
2016-03-02 14:30 ` Mark Lord [this message]
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