KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (6)

Status: moderation: reported on 2026/04/17 15:48
Subsystems: wireguard
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+b943b311fce5e5f92a7a@syzkaller.appspotmail.com
First crash: 104d, last: 34d
✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
9d667db5 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 (6) 2026/06/01 00:29 2026/06/01 00:29 2026/06/01 01:11 6b4a8443

			
		
3f888074 assessment-security 💥 KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (6) 2026/05/15 07:36 2026/05/15 07:36 2026/05/15 07:37 6ccb967e
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/45776d348471d68a01...
truncated to first 200 bytes; open job for full error
9a42b976 assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (6) 2026/04/13 15:38 2026/04/13 15:38 2026/04/13 15:58 1a086e7c

			
		
Similar bugs (5)
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 707d 707d 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 544d 544d 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 wireguard 6 2 811d 819d 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 431d 440d 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 222d 201d 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 0xffff88811a21c108 of 2 bytes by task 9289 on cpu 1:
 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:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 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 0xffff88811a21c108 of 16 bytes by task 3391 on cpu 0:
 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:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 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: 0 UID: 0 PID: 3391 Comm: kworker/0:5 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: wg-kex-wg1 wg_packet_handshake_receive_worker
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/22 11:00 upstream ef0c9f75a195 43bfcdb0 .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
2026/05/11 03:57 upstream 5d6919055dec 29233ece .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
2026/04/13 15:38 upstream 028ef9c96e96 9530ccf9 .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.