Commit e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()")
refactors pm8001_queue_command(), however it introduces a potential
cause of a double free scenario when it changes the function to return
-ENODEV in case of phy down/device gone state.

In this path, pm8001_queue_command updates task status and calls
task_done to indicate to upper layer that the task has been handled.
However, this also frees the underlying sas task. A -ENODEV is then
returned to the caller. When libsas sas_ata_qc_issue receives this error
value, it assumes the task wasn't handled/queued by LLDD and proceeds to
clean up and free the task again, resulting in a double free.

Since pm8001_queue_command handles the sas task in this case, it should
return 0 to the caller indicating that the task has been handled.

Fixes: e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()")
Signed-off-by: Salomon Dushimirimana <salomondush@google.com>
---
Changelog since v2:
- Added this changelog section

Changelog since v3:
- Added debug messsage to signal device gone issue

 drivers/scsi/pm8001/pm8001_sas.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/pm8001/pm8001_sas.c b/drivers/scsi/pm8001/pm8001_sas.c
index 6a8d35aea93a..645524f3fe2d 100644
--- a/drivers/scsi/pm8001/pm8001_sas.c
+++ b/drivers/scsi/pm8001/pm8001_sas.c
@@ -525,8 +525,9 @@ int pm8001_queue_command(struct sas_task *task, gfp_t gfp_flags)
 		} else {
 			task->task_done(task);
 		}
-		rc = -ENODEV;
-		goto err_out;
+		spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+		pm8001_dbg(pm8001_ha, IO, "pm8001_task_exec device gone\n");
+		return 0;
 	}
 
 	ccb = pm8001_ccb_alloc(pm8001_ha, pm8001_dev, task);
-- 
2.53.0.273.g2a3d683680-goog

On Fri, 13 Feb 2026 19:28:06 +0000, Salomon Dushimirimana wrote:

> Commit e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()")
> refactors pm8001_queue_command(), however it introduces a potential
> cause of a double free scenario when it changes the function to return
> -ENODEV in case of phy down/device gone state.
> 
> In this path, pm8001_queue_command updates task status and calls
> task_done to indicate to upper layer that the task has been handled.
> However, this also frees the underlying sas task. A -ENODEV is then
> returned to the caller. When libsas sas_ata_qc_issue receives this error
> value, it assumes the task wasn't handled/queued by LLDD and proceeds to
> clean up and free the task again, resulting in a double free.
> 
> [...]

Applied to 7.0/scsi-fixes, thanks!

[1/1] scsi: pm8001: Fix use-after-free in pm8001_queue_command()
      https://git.kernel.org/mkp/scsi/c/38353c26db28

-- 
Martin K. Petersen

Salomon,

> Commit e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()")
> refactors pm8001_queue_command(), however it introduces a potential
> cause of a double free scenario when it changes the function to return
> -ENODEV in case of phy down/device gone state.

Applied to 7.0/scsi-staging, thanks!

-- 
Martin K. Petersen

On 2/14/26 04:28, Salomon Dushimirimana wrote:
> Commit e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()")
> refactors pm8001_queue_command(), however it introduces a potential
> cause of a double free scenario when it changes the function to return
> -ENODEV in case of phy down/device gone state.
> 
> In this path, pm8001_queue_command updates task status and calls
> task_done to indicate to upper layer that the task has been handled.
> However, this also frees the underlying sas task. A -ENODEV is then
> returned to the caller. When libsas sas_ata_qc_issue receives this error
> value, it assumes the task wasn't handled/queued by LLDD and proceeds to
> clean up and free the task again, resulting in a double free.
> 
> Since pm8001_queue_command handles the sas task in this case, it should
> return 0 to the caller indicating that the task has been handled.
> 
> Fixes: e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()")
> Signed-off-by: Salomon Dushimirimana <salomondush@google.com>

Looks OK.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>


-- 
Damien Le Moal
Western Digital Research