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

Julian Wiedmann
2021-03-09T16:53:30Z

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@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.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