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authorBryan Whitehead <Bryan.Whitehead@microchip.com>2019-03-11 13:39:39 -0400
committerDavid S. Miller <davem@davemloft.net>2019-03-11 12:20:20 -0700
commitdd9d9f5907bb475f8b1796c47d4ecc7fb9b72136 (patch)
treed06f79fa359b2d3e3aadf5e9a037661eda9db333 /drivers/net/ethernet/microchip
parentnet: liquidio: fix a NULL pointer dereference (diff)
downloadlinux-dev-dd9d9f5907bb475f8b1796c47d4ecc7fb9b72136.tar.xz
linux-dev-dd9d9f5907bb475f8b1796c47d4ecc7fb9b72136.zip
lan743x: Fix RX Kernel Panic
It has been noticed that running the speed test at www.speedtest.net occasionally causes a kernel panic. Investigation revealed that under this test RX buffer allocation sometimes fails and returns NULL. But the lan743x driver did not handle this case. This patch fixes this issue by attempting to allocate a buffer before sending the new rx packet to the OS. If the allocation fails then the new rx packet is dropped and the existing buffer is reused in the DMA ring. Updates for v2: Additional 2 locations where allocation was not checked, has been changed to reuse existing buffer. Fixes: 23f0703c125b ("lan743x: Add main source files for new lan743x driver") Signed-off-by: Bryan Whitehead <Bryan.Whitehead@microchip.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/microchip')
-rw-r--r--drivers/net/ethernet/microchip/lan743x_main.c46
1 files changed, 32 insertions, 14 deletions
diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index 4d1b4a24907f..2876bab642e2 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -1902,7 +1902,17 @@ static int lan743x_rx_next_index(struct lan743x_rx *rx, int index)
return ((++index) % rx->ring_size);
}
-static int lan743x_rx_allocate_ring_element(struct lan743x_rx *rx, int index)
+static struct sk_buff *lan743x_rx_allocate_skb(struct lan743x_rx *rx)
+{
+ int length = 0;
+
+ length = (LAN743X_MAX_FRAME_SIZE + ETH_HLEN + 4 + RX_HEAD_PADDING);
+ return __netdev_alloc_skb(rx->adapter->netdev,
+ length, GFP_ATOMIC | GFP_DMA);
+}
+
+static int lan743x_rx_init_ring_element(struct lan743x_rx *rx, int index,
+ struct sk_buff *skb)
{
struct lan743x_rx_buffer_info *buffer_info;
struct lan743x_rx_descriptor *descriptor;
@@ -1911,9 +1921,7 @@ static int lan743x_rx_allocate_ring_element(struct lan743x_rx *rx, int index)
length = (LAN743X_MAX_FRAME_SIZE + ETH_HLEN + 4 + RX_HEAD_PADDING);
descriptor = &rx->ring_cpu_ptr[index];
buffer_info = &rx->buffer_info[index];
- buffer_info->skb = __netdev_alloc_skb(rx->adapter->netdev,
- length,
- GFP_ATOMIC | GFP_DMA);
+ buffer_info->skb = skb;
if (!(buffer_info->skb))
return -ENOMEM;
buffer_info->dma_ptr = dma_map_single(&rx->adapter->pdev->dev,
@@ -2060,8 +2068,19 @@ static int lan743x_rx_process_packet(struct lan743x_rx *rx)
/* packet is available */
if (first_index == last_index) {
/* single buffer packet */
+ struct sk_buff *new_skb = NULL;
int packet_length;
+ new_skb = lan743x_rx_allocate_skb(rx);
+ if (!new_skb) {
+ /* failed to allocate next skb.
+ * Memory is very low.
+ * Drop this packet and reuse buffer.
+ */
+ lan743x_rx_reuse_ring_element(rx, first_index);
+ goto process_extension;
+ }
+
buffer_info = &rx->buffer_info[first_index];
skb = buffer_info->skb;
descriptor = &rx->ring_cpu_ptr[first_index];
@@ -2081,7 +2100,7 @@ static int lan743x_rx_process_packet(struct lan743x_rx *rx)
skb_put(skb, packet_length - 4);
skb->protocol = eth_type_trans(skb,
rx->adapter->netdev);
- lan743x_rx_allocate_ring_element(rx, first_index);
+ lan743x_rx_init_ring_element(rx, first_index, new_skb);
} else {
int index = first_index;
@@ -2094,26 +2113,23 @@ static int lan743x_rx_process_packet(struct lan743x_rx *rx)
if (first_index <= last_index) {
while ((index >= first_index) &&
(index <= last_index)) {
- lan743x_rx_release_ring_element(rx,
- index);
- lan743x_rx_allocate_ring_element(rx,
- index);
+ lan743x_rx_reuse_ring_element(rx,
+ index);
index = lan743x_rx_next_index(rx,
index);
}
} else {
while ((index >= first_index) ||
(index <= last_index)) {
- lan743x_rx_release_ring_element(rx,
- index);
- lan743x_rx_allocate_ring_element(rx,
- index);
+ lan743x_rx_reuse_ring_element(rx,
+ index);
index = lan743x_rx_next_index(rx,
index);
}
}
}
+process_extension:
if (extension_index >= 0) {
descriptor = &rx->ring_cpu_ptr[extension_index];
buffer_info = &rx->buffer_info[extension_index];
@@ -2290,7 +2306,9 @@ static int lan743x_rx_ring_init(struct lan743x_rx *rx)
rx->last_head = 0;
for (index = 0; index < rx->ring_size; index++) {
- ret = lan743x_rx_allocate_ring_element(rx, index);
+ struct sk_buff *new_skb = lan743x_rx_allocate_skb(rx);
+
+ ret = lan743x_rx_init_ring_element(rx, index, new_skb);
if (ret)
goto cleanup;
}