[PATCH 6.18 188/314] scsi: core: Fix refcount leak for tagset_refcnt

Sasha Levin
2026-03-10T11:27:42Z

From: Junxiao Bi <junxiao.bi@oracle.com>

commit 1ac22c8eae81366101597d48360718dff9b9d980 upstream.

This leak will cause a hang when tearing down the SCSI host. For example,
iscsid hangs with the following call trace:

[130120.652718] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured

PID: 2528 TASK: ffff9d0408974e00 CPU: 3 COMMAND: "iscsid"
#0 [ffffb5b9c134b9e0] __schedule at ffffffff860657d4
#1 [ffffb5b9c134ba28] schedule at ffffffff86065c6f
#2 [ffffb5b9c134ba40] schedule_timeout at ffffffff86069fb0
#3 [ffffb5b9c134bab0] __wait_for_common at ffffffff8606674f
#4 [ffffb5b9c134bb10] scsi_remove_host at ffffffff85bfe84b
#5 [ffffb5b9c134bb30] iscsi_sw_tcp_session_destroy at ffffffffc03031c4 [iscsi_tcp]
#6 [ffffb5b9c134bb48] iscsi_if_recv_msg at ffffffffc0292692 [scsi_transport_iscsi]
#7 [ffffb5b9c134bb98] iscsi_if_rx at ffffffffc02929c2 [scsi_transport_iscsi]
#8 [ffffb5b9c134bbf0] netlink_unicast at ffffffff85e551d6
#9 [ffffb5b9c134bc38] netlink_sendmsg at ffffffff85e554ef

Fixes: 8fe4ce5836e9 ("scsi: core: Fix a use-after-free")
Cc: stable@vger.kernel.org
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260223232728.93350-1-junxiao.bi@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/scsi/scsi_scan.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 3c6e089e80c38..f405ef9c0e1e8 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -356,6 +356,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
* since we use this queue depth most of times.
*/
if (scsi_realloc_sdev_budget_map(sdev, depth)) {
+ kref_put(&sdev->host->tagset_refcnt, scsi_mq_free_tags);
put_device(&starget->dev);
kfree(sdev);
goto out;
--
2.51.0