From 93bf1d1e0ad78ea08390ccd1cb67a753162a93fd Mon Sep 17 00:00:00 2001
From: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Date: Thu, 27 Jan 2022 14:50:03 +0530
Subject: [PATCH 31/34] net: amd-xgbe: Fix skb data length underflow
Git-commit: 5aac9108a180fc06e28d4e7fb00247ce603b72ee
References: git-fixes
Patch-mainline: v5.17-rc3
There will be BUG_ON() triggered in include/linux/skbuff.h leading to
intermittent kernel panic, when the skb length underflow is detected.
Fix this by dropping the packet if such length underflows are seen
because of inconsistencies in the hardware descriptors.
Fixes: 622c36f143fc ("amd-xgbe: Fix jumbo MTU processing on newer hardware")
Suggested-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20220127092003.2812745-1-Shyam-sundar.S-k@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/ethernet/amd/xgbe/xgbe-drv.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index 6005ae02e479..970726f158cc 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -2553,6 +2553,14 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
buf2_len = xgbe_rx_buf2_len(rdata, packet, len);
len += buf2_len;
+ if (buf2_len > rdata->rx.buf.dma_len) {
+ /* Hardware inconsistency within the descriptors
+ * that has resulted in a length underflow.
+ */
+ error = 1;
+ goto skip_data;
+ }
+
if (!skb) {
skb = xgbe_create_skb(pdata, napi, rdata,
buf1_len);
@@ -2582,8 +2590,10 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
if (!last || context_next)
goto read_again;
- if (!skb)
+ if (!skb || error) {
+ dev_kfree_skb(skb);
goto next_packet;
+ }
/* Be sure we don't exceed the configured MTU */
max_len = netdev->mtu + ETH_HLEN;
--
2.16.4