KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (7)

Status: moderation: reported on 2026/09/10 17:16
Subsystems: wireguard
Labels: race:benign prio:high
[Documentation on labels]
Reported-by: syzbot+b0cbb110925a04dd3a97@syzkaller.appspotmail.com
First crash: 4d04h, last: 4d04h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
3f90532e assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ✅ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ✅ KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (7) 2026/09/08 01:22 2026/09/08 01:22 2026/09/08 01:24 680aa3e1
8dca0dd9 assessment-kcsan Benign: ✅ KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (7) 2026/09/06 17:09 2026/09/06 17:09 2026/09/06 17:28 4f7b22a0
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (2) wireguard 6 1 753d 753d 0/29 auto-obsoleted due to no activity on 2024/09/22 04:23
upstream KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (3) wireguard 6 1 589d 589d 0/29 auto-obsoleted due to no activity on 2025/03/26 00:12
upstream KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (6) prio:high wireguard 6 3 80d 146d 0/29 auto-obsoleted due to no activity on 2026/08/17 11:01
upstream KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint wireguard 6 2 857d 865d 0/29 auto-obsoleted due to no activity on 2024/06/10 05:06
upstream KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (4) wireguard 6 2 477d 486d 0/29 auto-obsoleted due to no activity on 2025/07/16 14:38
upstream KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (5) wireguard 6 3 268d 247d 0/29 auto-obsoleted due to no activity on 2026/02/10 21:40

Sample crash report:
==================================================================
BUG: KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint

read to 0xffff88811b17a748 of 2 bytes by task 3598 on cpu 0:
 endpoint_eq drivers/net/wireguard/socket.c:259 [inline]
 wg_socket_set_peer_endpoint+0x1c4/0x440 drivers/net/wireguard/socket.c:280
 wg_socket_set_peer_endpoint_from_skb+0x6d/0xa0 drivers/net/wireguard/socket.c:304
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:150 [inline]
 wg_packet_handshake_receive_worker+0x375/0x570 drivers/net/wireguard/receive.c:213
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

write to 0xffff88811b17a748 of 16 bytes by task 37 on cpu 1:
 wg_socket_set_peer_endpoint+0x3ac/0x440 drivers/net/wireguard/socket.c:284
 wg_socket_set_peer_endpoint_from_skb+0x6d/0xa0 drivers/net/wireguard/socket.c:304
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:172 [inline]
 wg_packet_handshake_receive_worker+0x3a2/0x570 drivers/net/wireguard/receive.c:213
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3479
 worker_thread+0x569/0x750 kernel/workqueue.c:3560
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 37 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: wg-kex-wg1 wg_packet_handshake_receive_worker
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/06 17:09 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint
* Struck through repros no longer work on HEAD.