Looks good to me.
Reviewed-by: Subhash Jadavani <subha...@codeaurora.org>


> A race condition appear to exist between request completion when
> scsi_done() is called to end the request and set the tag back to
> -1 (at blk_queue_end_tag() scsi_end_request), and scsi layer error
> handling which aborts the command and reuses it to request sense
> data. Sending the request sense is done with tag which was set to -1
> and so it is invalid.
> Assert command tag passed from scsi layer is valid.
>
> Signed-off-by: Gilad Broner <gbro...@codeaurora.org>
> Signed-off-by: Yaniv Gardi <yga...@codeaurora.org>
>
> ---
>  drivers/scsi/ufs/ufshcd.c | 24 ++++++++++++++++++++++--
>  1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 2d3ebca..8860a57 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -190,6 +190,10 @@ static int ufshcd_config_pwr_mode(struct ufs_hba
> *hba,
>               struct ufs_pa_layer_attr *desired_pwr_mode);
>  static int ufshcd_change_power_mode(struct ufs_hba *hba,
>                            struct ufs_pa_layer_attr *pwr_mode);
> +static inline bool ufshcd_valid_tag(struct ufs_hba *hba, int tag)
> +{
> +     return tag >= 0 && tag < hba->nutrs;
> +}
>
>  static inline int ufshcd_enable_irq(struct ufs_hba *hba)
>  {
> @@ -1310,6 +1314,12 @@ static int ufshcd_queuecommand(struct Scsi_Host
> *host, struct scsi_cmnd *cmd)
>       hba = shost_priv(host);
>
>       tag = cmd->request->tag;
> +     if (!ufshcd_valid_tag(hba, tag)) {
> +             dev_err(hba->dev,
> +                     "%s: invalid command tag %d: cmd=0x%p, 
> cmd->request=0x%p",
> +                     __func__, tag, cmd, cmd->request);
> +             BUG();
> +     }
>
>       spin_lock_irqsave(hba->host->host_lock, flags);
>       switch (hba->ufshcd_state) {
> @@ -3862,13 +3872,23 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
>       host = cmd->device->host;
>       hba = shost_priv(host);
>       tag = cmd->request->tag;
> +     if (!ufshcd_valid_tag(hba, tag)) {
> +             dev_err(hba->dev,
> +                     "%s: invalid command tag %d: cmd=0x%p, 
> cmd->request=0x%p",
> +                     __func__, tag, cmd, cmd->request);
> +             BUG();
> +     }
>
>       ufshcd_hold(hba, false);
> +     reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
>       /* If command is already aborted/completed, return SUCCESS */
> -     if (!(test_bit(tag, &hba->outstanding_reqs)))
> +     if (!(test_bit(tag, &hba->outstanding_reqs))) {
> +             dev_err(hba->dev,
> +                     "%s: cmd at tag %d already completed, outstanding=0x%lx,
> doorbell=0x%x\n",
> +                     __func__, tag, hba->outstanding_reqs, reg);
>               goto out;
> +     }
>
> -     reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
>       if (!(reg & (1 << tag))) {
>               dev_err(hba->dev,
>               "%s: cmd was completed, but without a notifying intr, tag = %d",
> --
> 1.8.5.2
>
> --
> QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
> --
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