netdev - [PATCH net 1/4] s390/qeth: fix memory leak after failed TX Buffer allocation

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Message-Id: <20210309165221.1735641-2-jwi@linux.ibm.com>
Date:   Tue,  9 Mar 2021 17:52:18 +0100
From:   Julian Wiedmann <jwi@...ux.ibm.com>
To:     David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     linux-netdev <netdev@...r.kernel.org>,
        linux-s390 <linux-s390@...r.kernel.org>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Karsten Graul <kgraul@...ux.ibm.com>,
        Julian Wiedmann <jwi@...ux.ibm.com>
Subject: [PATCH net 1/4] s390/qeth: fix memory leak after failed TX Buffer allocation

When qeth_alloc_qdio_queues() fails to allocate one of the buffers that
back an Output Queue, the 'out_freeoutqbufs' path will free all
previously allocated buffers for this queue. But it misses to free the
half-finished queue struct itself.

Move the buffer allocation into qeth_alloc_output_queue(), and deal with
such errors internally.

Fixes: 0da9581ddb0f ("qeth: exploit asynchronous delivery of storage blocks")
Signed-off-by: Julian Wiedmann <jwi@...ux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@...ux.ibm.com>
---
 drivers/s390/net/qeth_core_main.c | 35 +++++++++++++++----------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index b71b8902d1c4..f7bc0ca6909b 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2634,15 +2634,28 @@ static void qeth_free_output_queue(struct qeth_qdio_out_q *q)
 static struct qeth_qdio_out_q *qeth_alloc_output_queue(void)
 {
 	struct qeth_qdio_out_q *q = kzalloc(sizeof(*q), GFP_KERNEL);
+	unsigned int i;
 
 	if (!q)
 		return NULL;
 
-	if (qdio_alloc_buffers(q->qdio_bufs, QDIO_MAX_BUFFERS_PER_Q)) {
-		kfree(q);
-		return NULL;
+	if (qdio_alloc_buffers(q->qdio_bufs, QDIO_MAX_BUFFERS_PER_Q))
+		goto err_qdio_bufs;
+
+	for (i = 0; i < QDIO_MAX_BUFFERS_PER_Q; i++) {
+		if (qeth_init_qdio_out_buf(q, i))
+			goto err_out_bufs;
 	}
+
 	return q;
+
+err_out_bufs:
+	while (i > 0)
+		kmem_cache_free(qeth_qdio_outbuf_cache, q->bufs[--i]);
+	qdio_free_buffers(q->qdio_bufs, QDIO_MAX_BUFFERS_PER_Q);
+err_qdio_bufs:
+	kfree(q);
+	return NULL;
 }
 
 static void qeth_tx_completion_timer(struct timer_list *timer)
@@ -2655,7 +2668,7 @@ static void qeth_tx_completion_timer(struct timer_list *timer)
 
 static int qeth_alloc_qdio_queues(struct qeth_card *card)
 {
-	int i, j;
+	unsigned int i;
 
 	QETH_CARD_TEXT(card, 2, "allcqdbf");
 
@@ -2689,13 +2702,6 @@ static int qeth_alloc_qdio_queues(struct qeth_card *card)
 		queue->coalesce_usecs = QETH_TX_COALESCE_USECS;
 		queue->max_coalesced_frames = QETH_TX_MAX_COALESCED_FRAMES;
 		queue->priority = QETH_QIB_PQUE_PRIO_DEFAULT;
-
-		/* give outbound qeth_qdio_buffers their qdio_buffers */
-		for (j = 0; j < QDIO_MAX_BUFFERS_PER_Q; ++j) {
-			WARN_ON(queue->bufs[j]);
-			if (qeth_init_qdio_out_buf(queue, j))
-				goto out_freeoutqbufs;
-		}
 	}
 
 	/* completion */
@@ -2704,13 +2710,6 @@ static int qeth_alloc_qdio_queues(struct qeth_card *card)
 
 	return 0;
 
-out_freeoutqbufs:
-	while (j > 0) {
-		--j;
-		kmem_cache_free(qeth_qdio_outbuf_cache,
-				card->qdio.out_qs[i]->bufs[j]);
-		card->qdio.out_qs[i]->bufs[j] = NULL;
-	}
 out_freeoutq:
 	while (i > 0) {
 		qeth_free_output_queue(card->qdio.out_qs[--i]);
-- 
2.25.1