On 07/11/2018 03:44 PM, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The check of nvmebuf suggests that it can be null, however a recent
> change dereferences it to determine oxid before it is null checked,
> hence there is a potential null deference on the pointer. Fix this
> by performing the null check first. Also remove the oxid from the
> debug log message as this is no longer valid. I considered an early
> fetch of oxid if nvmebuf was valid, however, what oxid should be set
> to if nvembuf is null could lead to an ambiguous logging of an invalid
> oxid, so I thought just removing it from the logging was the least
> confusion solution.
I think that the 'if (!nvmebuf)' test is not needed and it would be better to remove the
tests (it is tested for the second time later in the function).
Tomas
>
> Detected by CoverityScan, CID#1471753 ("Dereference before null check")
>
> Fixes: 68c9b55deea5 ("scsi: lpfc: Fix abort error path for NVMET")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> drivers/scsi/lpfc/lpfc_nvmet.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/lpfc/lpfc_nvmet.c b/drivers/scsi/lpfc/lpfc_nvmet.c
> index 22f8a204b69f..01652d9ac619 100644
> --- a/drivers/scsi/lpfc/lpfc_nvmet.c
> +++ b/drivers/scsi/lpfc/lpfc_nvmet.c
> @@ -1742,12 +1742,9 @@ lpfc_nvmet_unsol_ls_buffer(struct lpfc_hba *phba, struct lpfc_sli_ring *pring,
> uint32_t *payload;
> uint32_t size, oxid, sid, rc;
>
> - fc_hdr = (struct fc_frame_header *)(nvmebuf->hbuf.virt);
> - oxid = be16_to_cpu(fc_hdr->fh_ox_id);
> -
> if (!nvmebuf || !phba->targetport) {
> lpfc_printf_log(phba, KERN_ERR, LOG_NVME_IOERR,
> - "6154 LS Drop IO x%x\n", oxid);
> + "6154 LS Drop IO\n");
> oxid = 0;
> size = 0;
> sid = 0;
> @@ -1755,6 +1752,9 @@ lpfc_nvmet_unsol_ls_buffer(struct lpfc_hba *phba, struct lpfc_sli_ring *pring,
> goto dropit;
> }
>
> + fc_hdr = (struct fc_frame_header *)(nvmebuf->hbuf.virt);
> + oxid = be16_to_cpu(fc_hdr->fh_ox_id);
> +
> tgtp = (struct lpfc_nvmet_tgtport *)phba->targetport->private;
> payload = (uint32_t *)(nvmebuf->dbuf.virt);
> size = bf_get(lpfc_rcqe_length, &nvmebuf->cq_event.cqe.rcqe_cmpl);
