Re: [PATCH][V2] scsi: cxgb3i: remove redundant null check and kfree on skb

Johannes Thumshirn
2017-03-14T11:34:31Z

On Tue, Mar 14, 2017 at 10:48:43AM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> On the error exit path, skb is always null, so the non-null check
> and __kfree_skb call are redundant. Remove the redundant code and
> just directly return with the appropriate error return code.
>
> Detected by CoverityScan, CID#114328 ("Logically Dead Code")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/scsi/cxgbi/cxgb3i/cxgb3i.c | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
> index 1880eb6..3c9f8cf2 100644
> --- a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
> +++ b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
> @@ -979,14 +979,14 @@ static int init_act_open(struct cxgbi_sock *csk)
> csk->atid = cxgb3_alloc_atid(t3dev, &t3_client, csk);
> if (csk->atid < 0) {
> pr_err("NO atid available.\n");
> - goto rel_resource;
> + return -EINVAL;
> }
> cxgbi_sock_set_flag(csk, CTPF_HAS_ATID);
> cxgbi_sock_get(csk);
>
> skb = alloc_wr(sizeof(struct cpl_act_open_req), 0, GFP_KERNEL);
> if (!skb)
> - goto rel_resource;
> + return -ENOMEM;

I don't think that's correct, not that it was before. cxgbi_sock_get(csk) does a
kref_get(&csk->refcnt), so this will at lease leak a kref. It will also "leak"
the atids_in_use in cxgb3_alloc_atid() as there's a call to cxgb3_free_atid()
missing. Looks like the complete cleanup path is worng here.

But I'd prefer having Karen or someone else at Chelsio confirm my assumptions.

Thanks,
Johannes

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Johannes Thumshirn Storage
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