[PATCH 4.20 128/171] s390/qeth: conclude all event processing before offlining a card

Greg Kroah-Hartman
2019-03-12T17:55:53Z

[ Upstream commit c0a2e4d10d9366ada133a8ae4ff2f32397f8b15b ]

Work for Bridgeport events is currently placed on a driver-wide
workqueue. If the card is removed and freed while any such work is still
active, this causes a use-after-free.
So put the events on a per-card queue, where we can control their
lifetime. As we also don't want stale events to last beyond an
offline & online cycle, flush this queue when setting the card offline.

Fixes: b4d72c08b358 ("qeth: bridgeport support - basic control")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/net/qeth_core.h | 2 +-
drivers/s390/net/qeth_core_main.c | 10 ++++++++--
drivers/s390/net/qeth_l2_main.c | 6 ++++--
drivers/s390/net/qeth_l3_main.c | 2 ++
4 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 8999be74c545..8f2af450152f 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -791,6 +791,7 @@ struct qeth_card {
struct qeth_seqno seqno;
struct qeth_card_options options;

+ struct workqueue_struct *event_wq;
wait_queue_head_t wait_q;
spinlock_t mclock;
unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)];
@@ -969,7 +970,6 @@ extern const struct attribute_group *qeth_osn_attr_groups[];
extern const struct attribute_group qeth_device_attr_group;
extern const struct attribute_group qeth_device_blkt_group;
extern const struct device_type qeth_generic_devtype;
-extern struct workqueue_struct *qeth_wq;

int qeth_card_hw_is_reachable(struct qeth_card *);
const char *qeth_get_cardname_short(struct qeth_card *);
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 89cc172820ca..ebbc3ad504f9 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -76,8 +76,7 @@ static void qeth_notify_skbs(struct qeth_qdio_out_q *queue,
static void qeth_release_skbs(struct qeth_qdio_out_buffer *buf);
static int qeth_init_qdio_out_buf(struct qeth_qdio_out_q *, int);

-struct workqueue_struct *qeth_wq;
-EXPORT_SYMBOL_GPL(qeth_wq);
+static struct workqueue_struct *qeth_wq;

int qeth_card_hw_is_reachable(struct qeth_card *card)
{
@@ -1471,6 +1470,10 @@ static struct qeth_card *qeth_alloc_card(struct ccwgroup_device *gdev)
CARD_RDEV(card) = gdev->cdev[0];
CARD_WDEV(card) = gdev->cdev[1];
CARD_DDEV(card) = gdev->cdev[2];
+
+ card->event_wq = alloc_ordered_workqueue("%s", 0, dev_name(&gdev->dev));
+ if (!card->event_wq)
+ goto out_wq;
if (qeth_setup_channel(&card->read, true))
goto out_ip;
if (qeth_setup_channel(&card->write, true))
@@ -1486,6 +1489,8 @@ static struct qeth_card *qeth_alloc_card(struct ccwgroup_device *gdev)
out_channel:
qeth_clean_channel(&card->read);
out_ip:
+ destroy_workqueue(card->event_wq);
+out_wq:
dev_set_drvdata(&gdev->dev, NULL);
kfree(card);
out:
@@ -5038,6 +5043,7 @@ static void qeth_core_free_card(struct qeth_card *card)
qeth_clean_channel(&card->read);
qeth_clean_channel(&card->write);
qeth_clean_channel(&card->data);
+ destroy_workqueue(card->event_wq);
qeth_free_qdio_buffers(card);
unregister_service_level(&card->qeth_service_level);
dev_set_drvdata(&card->gdev->dev, NULL);
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 49fa09c67d49..a6c55cbf3d69 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -391,6 +391,8 @@ static void qeth_l2_stop_card(struct qeth_card *card, int recovery_mode)
qeth_clear_cmd_buffers(&card->read);
qeth_clear_cmd_buffers(&card->write);
}
+
+ flush_workqueue(card->event_wq);
}

static int qeth_l2_process_inbound_buffer(struct qeth_card *card,
@@ -1455,7 +1457,7 @@ static void qeth_bridge_state_change(struct qeth_card *card,
data->card = card;
memcpy(&data->qports, qports,
sizeof(struct qeth_sbp_state_change) + extrasize);
- queue_work(qeth_wq, &data->worker);
+ queue_work(card->event_wq, &data->worker);
}

struct qeth_bridge_host_data {
@@ -1527,7 +1529,7 @@ static void qeth_bridge_host_event(struct qeth_card *card,
data->card = card;
memcpy(&data->hostevs, hostevs,
sizeof(struct qeth_ipacmd_addr_change) + extrasize);
- queue_work(qeth_wq, &data->worker);
+ queue_work(card->event_wq, &data->worker);
}

/* SETBRIDGEPORT support; sending commands */
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index d1bf55b5c8e1..29a2408b9282 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -1436,6 +1436,8 @@ static void qeth_l3_stop_card(struct qeth_card *card, int recovery_mode)
qeth_clear_cmd_buffers(&card->read);
qeth_clear_cmd_buffers(&card->write);
}
+
+ flush_workqueue(card->event_wq);
}

/*
--
2.19.1