Re: [PATCH] scsi: qla2xxx: avoid crash in qlt_handle_abts_completion() if mcmd == NULL

[Roman Bolshakov]

Hi Thomas,

The fix for the issue was sent earlier:
https://patchwork.kernel.org/patch/11141981/

It's not important to me what fixes goes into tree but I'd like to keep
the commit message because it covers how the situation arises. Also, the
cover letter of the patch series points out another issue not covered in
either of the fixes (lack of explicit LOGO instead of BA_RJT).

Thank you,
Roman

On Mon, Nov 04, 2019 at 01:18:03PM -0500, Thomas Abraham wrote:
> qlt_ctio_to_cmd() will return a NULL mcmd if h == QLA_TGT_SKIP_HANDLE. If
> the error subcodes don't match the exact codes checked a crash will occur
> when calling free_mcmd on the null mcmd
> 
> Signed-off-by: Thomas Abraham <tabraham@xxxxxxxx>
> ---
>  drivers/scsi/qla2xxx/qla_target.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
> index a06e56224a55..611ab224662f 100644
> --- a/drivers/scsi/qla2xxx/qla_target.c
> +++ b/drivers/scsi/qla2xxx/qla_target.c
> @@ -5732,7 +5732,8 @@ static void qlt_handle_abts_completion(struct scsi_qla_host *vha,
>  			    vha->vp_idx, entry->compl_status,
>  			    entry->error_subcode1,
>  			    entry->error_subcode2);
> -			ha->tgt.tgt_ops->free_mcmd(mcmd);
> +			if (mcmd)
> +				ha->tgt.tgt_ops->free_mcmd(mcmd);
>  		}
>  	} else if (mcmd) {
>  		ha->tgt.tgt_ops->free_mcmd(mcmd);
> -- 
> 2.16.4
>