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KCSAN: data-race in wg_socket_set_peer_endpoint / wg_socket_set_peer_endpoint (5)

Status: moderation: reported on 2026/01/06 17:58
Subsystems: wireguard
[Documentation on labels]
Reported-by: syzbot+dd0dccb9fba80e33b63d@syzkaller.appspotmail.com
First crash: 133d, last: 32d
Similar bugs (4)
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 518d 518d 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 354d 354d 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 622d 630d 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 242d 251d 0/29 auto-obsoleted due to no activity on 2025/07/16 14:38

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

read to 0xffff88811a54c108 of 2 bytes by task 3488 on cpu 0:
 endpoint_eq drivers/net/wireguard/socket.c:265 [inline]
 wg_socket_set_peer_endpoint+0x61/0x440 drivers/net/wireguard/socket.c:281
 wg_socket_set_peer_endpoint_from_skb+0x6d/0xa0 drivers/net/wireguard/socket.c:305
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:150 [inline]
 wg_packet_handshake_receive_worker+0x3c4/0x5d0 drivers/net/wireguard/receive.c:213
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

write to 0xffff88811a54c108 of 16 bytes by task 23 on cpu 1:
 wg_socket_set_peer_endpoint+0x3b6/0x440 drivers/net/wireguard/socket.c:285
 wg_socket_set_peer_endpoint_from_skb+0x6d/0xa0 drivers/net/wireguard/socket.c:305
 wg_receive_handshake_packet drivers/net/wireguard/receive.c:172 [inline]
 wg_packet_handshake_receive_worker+0x3f1/0x5d0 drivers/net/wireguard/receive.c:213
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 23 Comm: kworker/1:0 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: wg-kex-wg0 wg_packet_handshake_receive_worker
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/16 21:39 upstream 40fbbd64bba6 d6526ea3 .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
2025/10/29 10:58 upstream 8eefed8f65cc fd2207e7 .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
2025/09/07 04:45 upstream b236920731dd d291dd2d .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.