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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, John Garry <john.garry@huawei.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 162/177] scsi: libsas: Use _safe() loop in sas_resume_port()
Date:   Mon, 31 May 2021 15:15:19 +0200
Message-Id: <20210531130653.527014111@linuxfoundation.org>
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From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 8c7e7b8486cda21269d393245883c5e4737d5ee7 ]

If sas_notify_lldd_dev_found() fails then this code calls:

	sas_unregister_dev(port, dev);

which removes "dev", our list iterator, from the list.  This could lead to
an endless loop.  We need to use list_for_each_entry_safe().

Link: https://lore.kernel.org/r/YKUeq6gwfGcvvhty@mwanda
Fixes: 303694eeee5e ("[SCSI] libsas: suspend / resume support")
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/libsas/sas_port.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/libsas/sas_port.c b/drivers/scsi/libsas/sas_port.c
index 7c86fd248129..f751a12f92ea 100644
--- a/drivers/scsi/libsas/sas_port.c
+++ b/drivers/scsi/libsas/sas_port.c
@@ -25,7 +25,7 @@ static bool phy_is_wideport_member(struct asd_sas_port *port, struct asd_sas_phy
 
 static void sas_resume_port(struct asd_sas_phy *phy)
 {
-	struct domain_device *dev;
+	struct domain_device *dev, *n;
 	struct asd_sas_port *port = phy->port;
 	struct sas_ha_struct *sas_ha = phy->ha;
 	struct sas_internal *si = to_sas_internal(sas_ha->core.shost->transportt);
@@ -44,7 +44,7 @@ static void sas_resume_port(struct asd_sas_phy *phy)
 	 * 1/ presume every device came back
 	 * 2/ force the next revalidation to check all expander phys
 	 */
-	list_for_each_entry(dev, &port->dev_list, dev_list_node) {
+	list_for_each_entry_safe(dev, n, &port->dev_list, dev_list_node) {
 		int i, rc;
 
 		rc = sas_notify_lldd_dev_found(dev);
-- 
2.30.2