KCSAN: data-race in udp_tunnel6_xmit_skb / udp_tunnel6_xmit_skb (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3552c370 Merge tag 'nfsd-5.10-1' of git://linux-nfs.org/~b..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16b10532500000
kernel config: https://syzkaller.appspot.com/x/.config?x=671e27f23e60a67b
dashboard link: https://syzkaller.appspot.com/bug?extid=2e120b4c64e86ddf85b2
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [da...@davemloft.net ku...@kernel.org kuz...@ms2.inr.ac.ru linux-...@vger.kernel.org net...@vger.kernel.org yosh...@linux-ipv6.org]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2e120b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in udp_tunnel6_xmit_skb / udp_tunnel6_xmit_skb

read-write to 0xffff88800bf99130 of 8 bytes by task 21 on cpu 1:
iptunnel_xmit_stats include/net/ip_tunnels.h:458 [inline]
ip6tunnel_xmit include/net/ip6_tunnel.h:165 [inline]
udp_tunnel6_xmit_skb+0x3cf/0x420 net/ipv6/ip6_udp_tunnel.c:109
send6+0x2cd/0x3a0 drivers/net/wireguard/socket.c:152
wg_socket_send_skb_to_peer drivers/net/wireguard/socket.c:177 [inline]
wg_socket_send_buffer_to_peer+0x167/0x1e0 drivers/net/wireguard/socket.c:199
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0xf9/0x140 drivers/net/wireguard/send.c:51
process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
worker_thread+0x635/0xb90 kernel/workqueue.c:2418
kthread+0x1fa/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read-write to 0xffff88800bf99130 of 8 bytes by task 7 on cpu 0:
iptunnel_xmit_stats include/net/ip_tunnels.h:458 [inline]
ip6tunnel_xmit include/net/ip6_tunnel.h:165 [inline]
udp_tunnel6_xmit_skb+0x3cf/0x420 net/ipv6/ip6_udp_tunnel.c:109
send6+0x2cd/0x3a0 drivers/net/wireguard/socket.c:152
wg_socket_send_skb_to_peer+0xbb/0x120 drivers/net/wireguard/socket.c:177
wg_packet_create_data_done drivers/net/wireguard/send.c:252 [inline]
wg_packet_tx_worker+0x1e3/0x4c0 drivers/net/wireguard/send.c:280
process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
worker_thread+0x635/0xb90 kernel/workqueue.c:2418
kthread+0x1fa/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-crypt-wg0 wg_packet_tx_worker
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.