[moderation] [wireguard?] KCSAN: data-race in wg_socket_send_skb_to_peer / wg_socket_send_skb_to_peer (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f14faaf3a1fb Merge tag 'tsm-fixes-for-6.19' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=150a8a5a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8e27f4588a0f2183
dashboard link: https://syzkaller.appspot.com/bug?extid=7aaf0fda4d5e3ca1dd06
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
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/9cdf3c60fee1/disk-f14faaf3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/24b163320d00/vmlinux-f14faaf3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/854533a48cfc/bzImage-f14faaf3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7aaf0f...@syzkaller.appspotmail.com

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

read-write to 0xffff88811ad03d48 of 8 bytes by task 3427 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:3257 [inline]
process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3340
worker_thread+0x6bc/0x8b0 kernel/workqueue.c:3421
kthread+0x488/0x510 kernel/kthread.c:463
ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read-write to 0xffff88811ad03d48 of 8 bytes by task 37 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:3257 [inline]
process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3340
worker_thread+0x6bc/0x8b0 kernel/workqueue.c:3421
kthread+0x488/0x510 kernel/kthread.c:463
ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x000000000000014c -> 0x000000000000016c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 37 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker
==================================================================


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