[PATCH] ata: libata-scsi: Fix ata_scsi_port_error_handler() error path

[PATCH] ata: libata-scsi: Fix ata_scsi_port_error_handler() error path

[Damien Le Moal]

Commit 0c76106cb975 ("scsi: sd: Fix TCG OPAL unlock on system resume")
incorrectly handles scsi_resume_device() errors, leading to a double
call to spin_unlock_irqrestore() to unlock a device port. Fix this by
redefining the goto labels used in case of error and only unlock the
port scsi_scan_mutex when scsi_resume_device() fails.

Bug found with the Smatch static checker warning:

	drivers/ata/libata-scsi.c:4774 ata_scsi_dev_rescan()
	error: double unlocked 'ap->lock' (orig line 4757)

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 0c76106cb975 ("scsi: sd: Fix TCG OPAL unlock on system resume")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/ata/libata-scsi.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 2f4c58837641..e954976891a9 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -4745,7 +4745,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
 			 * bail out.
 			 */
 			if (ap->pflags & ATA_PFLAG_SUSPENDED)
-				goto unlock;
+				goto unlock_ap;
 
 			if (!sdev)
 				continue;
@@ -4758,7 +4758,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
 			if (do_resume) {
 				ret = scsi_resume_device(sdev);
 				if (ret == -EWOULDBLOCK)
-					goto unlock;
+					goto unlock_scan;
 				dev->flags &= ~ATA_DFLAG_RESUMING;
 			}
 			ret = scsi_rescan_device(sdev);
@@ -4766,12 +4766,13 @@ void ata_scsi_dev_rescan(struct work_struct *work)
 			spin_lock_irqsave(ap->lock, flags);
 
 			if (ret)
-				goto unlock;
+				goto unlock_ap;
 		}
 	}
 
-unlock:
+unlock_ap:
 	spin_unlock_irqrestore(ap->lock, flags);
+unlock_scan:
 	mutex_unlock(&ap->scsi_scan_mutex);
 
 	/* Reschedule with a delay if scsi_rescan_device() returned an error */
-- 
2.44.0

Re: [PATCH] ata: libata-scsi: Fix ata_scsi_port_error_handler() error path

[Niklas Cassel]

On Fri, Apr 12, 2024 at 08:47:31AM +0900, Damien Le Moal wrote:
> Commit 0c76106cb975 ("scsi: sd: Fix TCG OPAL unlock on system resume")
> incorrectly handles scsi_resume_device() errors, leading to a double
> call to spin_unlock_irqrestore() to unlock a device port. Fix this by
> redefining the goto labels used in case of error and only unlock the
> port scsi_scan_mutex when scsi_resume_device() fails.
> 
> Bug found with the Smatch static checker warning:
> 
> 	drivers/ata/libata-scsi.c:4774 ata_scsi_dev_rescan()
> 	error: double unlocked 'ap->lock' (orig line 4757)
> 
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Fixes: 0c76106cb975 ("scsi: sd: Fix TCG OPAL unlock on system resume")
> Cc: stable@vger.kernel.org
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>  drivers/ata/libata-scsi.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 2f4c58837641..e954976891a9 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -4745,7 +4745,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
>  			 * bail out.
>  			 */
>  			if (ap->pflags & ATA_PFLAG_SUSPENDED)
> -				goto unlock;
> +				goto unlock_ap;
>  
>  			if (!sdev)
>  				continue;
> @@ -4758,7 +4758,7 @@ void ata_scsi_dev_rescan(struct work_struct *work)
>  			if (do_resume) {
>  				ret = scsi_resume_device(sdev);
>  				if (ret == -EWOULDBLOCK)
> -					goto unlock;
> +					goto unlock_scan;
>  				dev->flags &= ~ATA_DFLAG_RESUMING;
>  			}
>  			ret = scsi_rescan_device(sdev);
> @@ -4766,12 +4766,13 @@ void ata_scsi_dev_rescan(struct work_struct *work)
>  			spin_lock_irqsave(ap->lock, flags);
>  
>  			if (ret)
> -				goto unlock;
> +				goto unlock_ap;
>  		}
>  	}
>  
> -unlock:
> +unlock_ap:
>  	spin_unlock_irqrestore(ap->lock, flags);
> +unlock_scan:
>  	mutex_unlock(&ap->scsi_scan_mutex);
>  
>  	/* Reschedule with a delay if scsi_rescan_device() returned an error */
> -- 
> 2.44.0
> 

Subject: [PATCH] ata: libata-scsi: Fix ata_scsi_port_error_handler() error path
ata_scsi_port_error_handler() ? How did you come up with that? :)
Wrong copy paste?

s/ata_scsi_port_error_handler()/ata_scsi_dev_rescan()/

With that:
Reviewed-by: Niklas Cassel <cassel@kernel.org>