Re: [PATCH][next] scsi: lpfc: fix pointer defereference before it is null checked issue

[James Smart <james.smart@broadcom.com>]

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On 11/18/2020 5:13 AM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> There is a null check on pointer lpfc_cmd after the pointer has been
> dereferenced when pointers rdata and ndlp are initialized at the start
> of the function. Fix this by only assigning rdata and ndlp after the
> pointer lpfc_cmd has been null checked.
>
> Addresses-Coverity: ("Dereference before null check")
> Fixes: 96e209be6ecb ("scsi: lpfc: Convert SCSI I/O completions to SLI-3 and SLI-4 handlers")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>   drivers/scsi/lpfc/lpfc_scsi.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
> index f989490359a5..3b989f720937 100644
> --- a/drivers/scsi/lpfc/lpfc_scsi.c
> +++ b/drivers/scsi/lpfc/lpfc_scsi.c
> @@ -4022,8 +4022,8 @@ lpfc_fcp_io_cmd_wqe_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pwqeIn,
>   	struct lpfc_io_buf *lpfc_cmd =
>   		(struct lpfc_io_buf *)pwqeIn->context1;
>   	struct lpfc_vport *vport = pwqeIn->vport;
> -	struct lpfc_rport_data *rdata = lpfc_cmd->rdata;
> -	struct lpfc_nodelist *ndlp = rdata->pnode;
> +	struct lpfc_rport_data *rdata;
> +	struct lpfc_nodelist *ndlp;
>   	struct scsi_cmnd *cmd;
>   	unsigned long flags;
>   	struct lpfc_fast_path_event *fast_path_evt;
> @@ -4040,6 +4040,9 @@ lpfc_fcp_io_cmd_wqe_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pwqeIn,
>   		return;
>   	}
>   
> +	rdata = lpfc_cmd->rdata;
> +	ndlp = rdata->pnode;
> +
>   	if (bf_get(lpfc_wcqe_c_xb, wcqe)) {
>   		/* TOREMOVE - currently this flag is checked during
>   		 * the release of lpfc_iocbq. Remove once we move

Looks good.

Reviewed-by: James Smart <james.smart@broadcom.com>

-- james


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