Re: [PATCH] scsi: smartpqi: Handle pqi_alloc_io_request() failure

[Don.Brace]

________________________________________
From: Triet Hoang <triet.hoang.dev@xxxxxxxxx>
Sent: Sunday, August 16, 2026 10:35 PM
To: Don Brace - C33706 <Don.Brace@xxxxxxxxxxxxx>
Cc: James.Bottomley@xxxxxxxxxxxxxxxxxxxxx <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>; martin.petersen@xxxxxxxxxx <martin.petersen@xxxxxxxxxx>; storagedev <storagedev@xxxxxxxxxxxxx>; linux-scsi@xxxxxxxxxxxxxxx <linux-scsi@xxxxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx <linux-kernel@xxxxxxxxxxxxxxx>; Triet Hoang <triet.hoang.dev@xxxxxxxxx>
Subject: [PATCH] scsi: smartpqi: Handle pqi_alloc_io_request() failure
 

Check the return value of pqi_alloc_io_request() before dereferencing
the returned request in pqi_submit_raid_request_synchronous() and
pqi_lun_reset().

Return SCSI_MLQUEUE_HOST_BUSY when a request cannot be allocated so that
the operation can be retried instead of dereferencing a NULL pointer.

Signed-off-by: Triet Hoang <triet.hoang.dev@xxxxxxxxx>

For internal/IOCTL requests (scmd == NULL), pqi_alloc_io_request() blocks until
one of the reserved slots is free rather than failing, so these two call sites
can never observe NULL. Only the scmd != NULL path can return NULL, and those
four callers -- pqi_raid_submit_io(), pqi_aio_submit_io(),
pqi_aio_submit_r1_write_io() and pqi_aio_submit_r56_write_io() -- already check
for it.

SCSI_MLQUEUE_HOST_BUSY (0x1055) is also only meaningful as a queuecommand()
return value. pqi_submit_raid_request_synchronous() returns 0/-errno to its
callers, and in pqi_lun_reset() a 0x1055 return would fall into the retry loop
in pqi_lun_reset_with_retries(), adding 30 seconds of msleep() to error
recovery before failing.

Nacked-by: Don Brace <don.brace@xxxxxxxxxxxxx>

---
 drivers/scsi/smartpqi/smartpqi_init.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index 5ec583dc2e7d..0930decef404 100644
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -4667,6 +4667,10 @@ static int pqi_submit_raid_request_synchronous(struct pqi_ctrl_info *ctrl_info,
        }

        io_request = pqi_alloc_io_request(ctrl_info, NULL);
+       if (!io_request) {
+               rc = SCSI_MLQUEUE_HOST_BUSY;
+               goto out;
+       }

        put_unaligned_le16(io_request->index,
                &(((struct pqi_raid_path_request *)request)->request_id));
@@ -6353,6 +6357,9 @@ static int pqi_lun_reset(struct pqi_ctrl_info *ctrl_info, struct pqi_scsi_dev *d
        struct pqi_task_management_request *request;

        io_request = pqi_alloc_io_request(ctrl_info, NULL);
+       if (!io_request)
+               return SCSI_MLQUEUE_HOST_BUSY;
+
        io_request->io_complete_callback = pqi_lun_reset_complete;
        io_request->context = &wait;

--
2.53.0