netdev - [PATCH net 1/6] s390/qeth: fix qdio teardown after early init error

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Date:   Mon, 23 Dec 2019 15:03:21 +0100
From:   Julian Wiedmann <jwi@...ux.ibm.com>
To:     David Miller <davem@...emloft.net>
Cc:     <netdev@...r.kernel.org>, <linux-s390@...r.kernel.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Stefan Raspl <raspl@...ux.ibm.com>,
        Ursula Braun <ubraun@...ux.ibm.com>,
        Julian Wiedmann <jwi@...ux.ibm.com>
Subject: [PATCH net 1/6] s390/qeth: fix qdio teardown after early init error

qeth_l?_set_online() goes through a number of initialization steps, and
on any error uses qeth_l?_stop_card() to tear down the residual state.

The first initialization step is qeth_core_hardsetup_card(). When this
fails after having established a QDIO context on the device
(ie. somewhere after qeth_mpc_initialize()), qeth_l?_stop_card() doesn't
shut down this QDIO context again (since the card state hasn't
progressed from DOWN at this stage).

Even worse, we then call qdio_free() as final teardown step to free the
QDIO data structures - while some of them are still hooked into wider
QDIO infrastructure such as the IRQ list. This is inevitably followed by
use-after-frees and other nastyness.

Fix this by unconditionally calling qeth_qdio_clear_card() to shut down
the QDIO context, and also to halt/clear any pending activity on the
various IO channels.
Remove the naive attempt at handling the teardown in
qeth_mpc_initialize(), it clearly doesn't suffice and we're handling it
properly now in the wider teardown code.

Fixes: 4a71df50047f ("qeth: new qeth device driver")
Signed-off-by: Julian Wiedmann <jwi@...ux.ibm.com>
---
 drivers/s390/net/qeth_core_main.c | 20 ++++++++------------
 drivers/s390/net/qeth_l2_main.c   |  2 +-
 drivers/s390/net/qeth_l3_main.c   |  2 +-
 3 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index bc4158888af9..324cf22f9111 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2482,50 +2482,46 @@ static int qeth_mpc_initialize(struct qeth_card *card)
 	rc = qeth_cm_enable(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "2err%d", rc);
-		goto out_qdio;
+		return rc;
 	}
 	rc = qeth_cm_setup(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "3err%d", rc);
-		goto out_qdio;
+		return rc;
 	}
 	rc = qeth_ulp_enable(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "4err%d", rc);
-		goto out_qdio;
+		return rc;
 	}
 	rc = qeth_ulp_setup(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "5err%d", rc);
-		goto out_qdio;
+		return rc;
 	}
 	rc = qeth_alloc_qdio_queues(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "5err%d", rc);
-		goto out_qdio;
+		return rc;
 	}
 	rc = qeth_qdio_establish(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "6err%d", rc);
 		qeth_free_qdio_queues(card);
-		goto out_qdio;
+		return rc;
 	}
 	rc = qeth_qdio_activate(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "7err%d", rc);
-		goto out_qdio;
+		return rc;
 	}
 	rc = qeth_dm_act(card);
 	if (rc) {
 		QETH_CARD_TEXT_(card, 2, "8err%d", rc);
-		goto out_qdio;
+		return rc;
 	}
 
 	return 0;
-out_qdio:
-	qeth_qdio_clear_card(card, !IS_IQD(card));
-	qdio_free(CARD_DDEV(card));
-	return rc;
 }
 
 void qeth_print_status_message(struct qeth_card *card)
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 8c95e6019bac..15e2fd65d434 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -287,12 +287,12 @@ static void qeth_l2_stop_card(struct qeth_card *card)
 		card->state = CARD_STATE_HARDSETUP;
 	}
 	if (card->state == CARD_STATE_HARDSETUP) {
-		qeth_qdio_clear_card(card, 0);
 		qeth_drain_output_queues(card);
 		qeth_clear_working_pool_list(card);
 		card->state = CARD_STATE_DOWN;
 	}
 
+	qeth_qdio_clear_card(card, 0);
 	flush_workqueue(card->event_wq);
 	card->info.mac_bits &= ~QETH_LAYER2_MAC_REGISTERED;
 	card->info.promisc_mode = 0;
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 04e301de376f..5508ab89b518 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -1307,12 +1307,12 @@ static void qeth_l3_stop_card(struct qeth_card *card)
 		card->state = CARD_STATE_HARDSETUP;
 	}
 	if (card->state == CARD_STATE_HARDSETUP) {
-		qeth_qdio_clear_card(card, 0);
 		qeth_drain_output_queues(card);
 		qeth_clear_working_pool_list(card);
 		card->state = CARD_STATE_DOWN;
 	}
 
+	qeth_qdio_clear_card(card, 0);
 	flush_workqueue(card->event_wq);
 	card->info.promisc_mode = 0;
 }
-- 
2.17.1