From: Bart Van Assche <bvanassche@xxxxxxx> [ Upstream commit 64180742605f772d511903c9e50262afb13726c6 ] Make the following changes in ufshcd_abort(): - Return FAILED instead of SUCCESS if the abort handler notices that a SCSI command has already been completed. Returning SUCCESS in this case triggers a use-after-free and may trigger a kernel crash. - Fix the code for aborting SCSI commands submitted to a WLUN. The current approach for aborting SCSI commands that have been submitted to a WLUN and that timed out is as follows: - Report to the SCSI core that the command has completed successfully. Let the block layer free any data buffers associated with the command. - Mark the command as outstanding in 'outstanding_reqs'. - If the block layer tries to reuse the tag associated with the aborted command, busy-wait until the tag is freed. This approach can result in: - Memory corruption if the controller accesses the data buffer after the block layer has freed the associated data buffers. - A race condition if ufshcd_queuecommand() or ufshcd_exec_dev_cmd() checks the bit that corresponds to an aborted command in 'outstanding_reqs' after it has been cleared and before it is reset. - High energy consumption if ufshcd_queuecommand() repeatedly returns SCSI_MLQUEUE_HOST_BUSY. Fix this by reporting to the SCSI error handler that aborting a SCSI command failed if the SCSI command was submitted to a WLUN. Link: https://lore.kernel.org/r/20210722033439.26550-15-bvanassche@xxxxxxx Fixes: 7a7e66c65d41 ("scsi: ufs: Fix a race condition between ufshcd_abort() and eh_work()") Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx> Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx> Cc: Can Guo <cang@xxxxxxxxxxxxxx> Cc: Asutosh Das <asutoshd@xxxxxxxxxxxxxx> Cc: Avri Altman <avri.altman@xxxxxxx> Reviewed-by: Bean Huo <beanhuo@xxxxxxxxxx> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/scsi/ufs/ufshcd.c | 54 ++++++++++++++------------------------- 1 file changed, 19 insertions(+), 35 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 0fe559ddc789..1708d7ced527 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -2766,15 +2766,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) WARN_ON(ufshcd_is_clkgating_allowed(hba) && (hba->clk_gating.state != CLKS_ON)); - if (unlikely(test_bit(tag, &hba->outstanding_reqs))) { - if (hba->pm_op_in_progress) - set_host_byte(cmd, DID_BAD_TARGET); - else - err = SCSI_MLQUEUE_HOST_BUSY; - ufshcd_release(hba); - goto out; - } - lrbp = &hba->lrb[tag]; WARN_ON(lrbp->cmd); lrbp->cmd = cmd; @@ -2973,11 +2964,6 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, req->timeout = msecs_to_jiffies(2 * timeout); blk_mq_start_request(req); - if (unlikely(test_bit(tag, &hba->outstanding_reqs))) { - err = -EBUSY; - goto out; - } - lrbp = &hba->lrb[tag]; WARN_ON(lrbp->cmd); err = ufshcd_compose_dev_cmd(hba, lrbp, cmd_type, tag); @@ -6984,7 +6970,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) struct ufs_hba *hba; unsigned long flags; unsigned int tag; - int err = 0; + int err = FAILED; struct ufshcd_lrb *lrbp; u32 reg; @@ -7001,12 +6987,12 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) ufshcd_hold(hba, false); reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL); - /* If command is already aborted/completed, return SUCCESS */ + /* If command is already aborted/completed, return FAILED. */ 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; + goto release; } /* Print Transfer Request of aborted task */ @@ -7035,7 +7021,8 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) dev_err(hba->dev, "%s: cmd was completed, but without a notifying intr, tag = %d", __func__, tag); - goto cleanup; + __ufshcd_transfer_req_compl(hba, 1UL << tag); + goto release; } /* @@ -7048,36 +7035,33 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) */ if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN) { ufshcd_update_evt_hist(hba, UFS_EVT_ABORT, lrbp->lun); - __ufshcd_transfer_req_compl(hba, (1UL << tag)); - set_bit(tag, &hba->outstanding_reqs); + spin_lock_irqsave(host->host_lock, flags); hba->force_reset = true; ufshcd_schedule_eh_work(hba); spin_unlock_irqrestore(host->host_lock, flags); - goto out; + goto release; } /* Skip task abort in case previous aborts failed and report failure */ - if (lrbp->req_abort_skip) - err = -EIO; - else - err = ufshcd_try_to_abort_task(hba, tag); + if (lrbp->req_abort_skip) { + dev_err(hba->dev, "%s: skipping abort\n", __func__); + ufshcd_set_req_abort_skip(hba, hba->outstanding_reqs); + goto release; + } - if (!err) { -cleanup: - __ufshcd_transfer_req_compl(hba, (1UL << tag)); -out: - err = SUCCESS; - } else { + err = ufshcd_try_to_abort_task(hba, tag); + if (err) { dev_err(hba->dev, "%s: failed with err %d\n", __func__, err); ufshcd_set_req_abort_skip(hba, hba->outstanding_reqs); err = FAILED; + goto release; } - /* - * This ufshcd_release() corresponds to the original scsi cmd that got - * aborted here (as we won't get any IRQ for it). - */ + err = SUCCESS; + +release: + /* Matches the ufshcd_hold() call at the start of this function. */ ufshcd_release(hba); return err; } -- 2.30.2
