When mb-xdp is set and return is XDP_PASS, packet is converted from
xdp_buff to sk_buff with xdp_update_skb_shared_info() in
bnxt_xdp_build_skb().
bnxt_xdp_build_skb() passes incorrect truesize argument to
xdp_update_skb_shared_info().
The truesize is calculated as BNXT_RX_PAGE_SIZE * sinfo->nr_frags but
the skb_shared_info was wiped by napi_build_skb() before.
So it stores sinfo->nr_frags before bnxt_xdp_build_skb() and use it
instead of getting skb_shared_info from xdp_get_shared_info_from_buff().
Splat looks like:
------------[ cut here ]------------
WARNING: CPU: 2 PID: 0 at net/core/skbuff.c:6072 skb_try_coalesce+0x504/0x590
Modules linked in: xt_nat xt_tcpudp veth af_packet xt_conntrack nft_chain_nat xt_MASQUERADE nf_conntrack_netlink xfrm_user xt_addrtype nft_coms
CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 6.14.0-rc2+ #3
RIP: 0010:skb_try_coalesce+0x504/0x590
Code: 4b fd ff ff 49 8b 34 24 40 80 e6 40 0f 84 3d fd ff ff 49 8b 74 24 48 40 f6 c6 01 0f 84 2e fd ff ff 48 8d 4e ff e9 25 fd ff ff <0f> 0b e99
RSP: 0018:ffffb62c4120caa8 EFLAGS: 00010287
RAX: 0000000000000003 RBX: ffffb62c4120cb14 RCX: 0000000000000ec0
RDX: 0000000000001000 RSI: ffffa06e5d7dc000 RDI: 0000000000000003
RBP: ffffa06e5d7ddec0 R08: ffffa06e6120a800 R09: ffffa06e7a119900
R10: 0000000000002310 R11: ffffa06e5d7dcec0 R12: ffffe4360575f740
R13: ffffe43600000000 R14: 0000000000000002 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffffa0755f700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f147b76b0f8 CR3: 00000001615d4000 CR4: 00000000007506f0
PKRU: 55555554
Call Trace:
<IRQ>
? __warn+0x84/0x130
? skb_try_coalesce+0x504/0x590
? report_bug+0x18a/0x1a0
? handle_bug+0x53/0x90
? exc_invalid_op+0x14/0x70
? asm_exc_invalid_op+0x16/0x20
? skb_try_coalesce+0x504/0x590
inet_frag_reasm_finish+0x11f/0x2e0
ip_defrag+0x37a/0x900
ip_local_deliver+0x51/0x120
ip_sublist_rcv_finish+0x64/0x70
ip_sublist_rcv+0x179/0x210
ip_list_rcv+0xf9/0x130
How to reproduce:
<Node A>
ip link set $interface1 xdp obj xdp_pass.o
ip link set $interface1 mtu 9000 up
ip a a 10.0.0.1/24 dev $interface1
<Node B>
ip link set $interfac2 mtu 9000 up
ip a a 10.0.0.2/24 dev $interface2
ping 10.0.0.1 -s 65000
Following ping.py patch adds xdp-mb-pass case. so ping.py is going to be
able to reproduce this issue.
Fixes: 1dc4c557bfed ("bnxt: adding bnxt_xdp_build_skb to build skb from multibuffer xdp_buff")
Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx>
---
v3:
- Copy nr_frags instead of full copy.
v2:
- Do not use num_frags in the bnxt_xdp_build_skb().
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 8 ++++++++
drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 7b8b5b39c7bb..6b5fe4ee7a99 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -2038,6 +2038,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
struct rx_cmp_ext *rxcmp1;
u32 tmp_raw_cons = *raw_cons;
u16 cons, prod, cp_cons = RING_CMP(tmp_raw_cons);
+ struct skb_shared_info *sinfo;
struct bnxt_sw_rx_bd *rx_buf;
unsigned int len;
u8 *data_ptr, agg_bufs, cmp_type;
@@ -2164,6 +2165,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
false);
if (!frag_len)
goto oom_next_rx;
+
}
xdp_active = true;
}
@@ -2173,6 +2175,12 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
rc = 1;
goto next_rx;
}
+ if (xdp_buff_has_frags(&xdp)) {
+ sinfo = xdp_get_shared_info_from_buff(&xdp);
+ agg_bufs = sinfo->nr_frags;
+ } else {
+ agg_bufs = 0;
+ }
}
if (len <= bp->rx_copybreak) {
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index e6c64e4bd66c..e9b49cb5b735 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -476,7 +476,7 @@ bnxt_xdp_build_skb(struct bnxt *bp, struct sk_buff *skb, u8 num_frags,
}
xdp_update_skb_shared_info(skb, num_frags,
sinfo->xdp_frags_size,
- BNXT_RX_PAGE_SIZE * sinfo->nr_frags,
+ BNXT_RX_PAGE_SIZE * num_frags,
xdp_buff_is_frag_pfmemalloc(xdp));
return skb;
}
--
2.34.1
