From 34aeb4da20f93ac80a6291a2dbe7b9c6460e9b26 Mon Sep 17 00:00:00 2001 From: Shyam Sundar S K Date: Thu, 27 Jan 2022 14:50:03 +0530 Subject: [PATCH] net: amd-xgbe: Fix skb data length underflow commit 5aac9108a180fc06e28d4e7fb00247ce603b72ee upstream. 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 Signed-off-by: Shyam Sundar S K Acked-by: Tom Lendacky Link: https://lore.kernel.org/r/20220127092003.2812745-1-Shyam-sundar.S-k@amd.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- 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 5949d30ee9a53..35659f0dbe74e 100644 --- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c +++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c @@ -2768,6 +2768,14 @@ read_again: 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); @@ -2797,8 +2805,10 @@ skip_data: 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; -- 2.47.2