6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Aleksandr Mishin <amishin@xxxxxxxxxx>
[ Upstream commit eb592008f79be52ccef88cd9a5249b3fc0367278 ]
build_skb() returns NULL in case of a memory allocation failure so handle
it inside __octep_oq_process_rx() to avoid NULL pointer dereference.
__octep_oq_process_rx() is called during NAPI polling by the driver. If
skb allocation fails, keep on pulling packets out of the Rx DMA queue: we
shouldn't break the polling immediately and thus falsely indicate to the
octep_napi_poll() that the Rx pressure is going down. As there is no
associated skb in this case, don't process the packets and don't push them
up the network stack - they are skipped.
Helper function is implemented to unmmap/flush all the fragment buffers
used by the dropped packet. 'alloc_failures' counter is incremented to
mark the skb allocation error in driver statistics.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 37d79d059606 ("octeon_ep: add Tx/Rx processing and interrupt support")
Suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Aleksandr Mishin <amishin@xxxxxxxxxx>
Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
.../net/ethernet/marvell/octeon_ep/octep_rx.c | 27 +++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c
index cfbfad95b0211..c7f4e3c058b7f 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_rx.c
@@ -360,6 +360,27 @@ static void octep_oq_next_pkt(struct octep_oq *oq,
*read_idx = 0;
}
+/**
+ * octep_oq_drop_rx() - Free the resources associated with a packet.
+ *
+ * @oq: Octeon Rx queue data structure.
+ * @buff_info: Current packet buffer info.
+ * @read_idx: Current packet index in the ring.
+ * @desc_used: Current packet descriptor number.
+ *
+ */
+static void octep_oq_drop_rx(struct octep_oq *oq,
+ struct octep_rx_buffer *buff_info,
+ u32 *read_idx, u32 *desc_used)
+{
+ int data_len = buff_info->len - oq->max_single_buffer_size;
+
+ while (data_len > 0) {
+ octep_oq_next_pkt(oq, buff_info, read_idx, desc_used);
+ data_len -= oq->buffer_size;
+ };
+}
+
/**
* __octep_oq_process_rx() - Process hardware Rx queue and push to stack.
*
@@ -415,6 +436,12 @@ static int __octep_oq_process_rx(struct octep_device *oct,
octep_oq_next_pkt(oq, buff_info, &read_idx, &desc_used);
skb = build_skb((void *)resp_hw, PAGE_SIZE);
+ if (!skb) {
+ octep_oq_drop_rx(oq, buff_info,
+ &read_idx, &desc_used);
+ oq->stats.alloc_failures++;
+ continue;
+ }
skb_reserve(skb, data_offset);
rx_bytes += buff_info->len;
--
2.43.0
