scsi: core: Fix refcount leak for tagset_refcnt

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>

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 60c06fa4ec326d36b39924107068b0f83ef4055a..2cfcf1f5d6a4655109bca544015dce3d34317353 100644 (file)
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -361,6 +361,7 @@ 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;