[moderation] [wireguard?] KCSAN: data-race in wg_socket_send_skb_to_peer / wg_socket_send_skb_to_peer (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4a26e7032d7d Merge tag 'core-bugs-2025-12-01' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=160de192580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1cf5676573a33318
dashboard link: https://syzkaller.appspot.com/bug?extid=97539721cdda2fb6da93
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [Ja...@zx2c4.com andrew...@lunn.ch da...@davemloft.net edum...@google.com ku...@kernel.org linux-...@vger.kernel.org net...@vger.kernel.org pab...@redhat.com wire...@lists.zx2c4.com]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d6da4f1044e5/disk-4a26e703.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ee614a58c06e/vmlinux-4a26e703.xz
kernel image: https://storage.googleapis.com/syzbot-assets/43cbdf4a8d4f/bzImage-4a26e703.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+975397...@syzkaller.appspotmail.com

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

read-write to 0xffff88811af56a58 of 8 bytes by task 167 on cpu 1:
wg_socket_send_skb_to_peer+0xe8/0x130 drivers/net/wireguard/socket.c:183
wg_socket_send_buffer_to_peer+0xf1/0x120 drivers/net/wireguard/socket.c:200
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x10d/0x160 drivers/net/wireguard/send.c:51
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
worker_thread+0x582/0x770 kernel/workqueue.c:3427
kthread+0x489/0x510 kernel/kthread.c:463
ret_from_fork+0x13f/0x270 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read-write to 0xffff88811af56a58 of 8 bytes by task 3503 on cpu 0:
wg_socket_send_skb_to_peer+0xe8/0x130 drivers/net/wireguard/socket.c:183
wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline]
wg_packet_tx_worker+0x12d/0x330 drivers/net/wireguard/send.c:276
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
worker_thread+0x582/0x770 kernel/workqueue.c:3427
kthread+0x489/0x510 kernel/kthread.c:463
ret_from_fork+0x13f/0x270 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x000000000000005c -> 0x00000000000000f0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3503 Comm: kworker/0:9 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: wg-crypt-wg2 wg_packet_tx_worker
==================================================================


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