KCSAN: data-race in audit_log_start / audit_receive (4)

Status: moderation: reported on 2026/08/11 04:14
Subsystems: audit
Labels: race:benign prio:low
[Documentation on labels]
Reported-by: syzbot+39b8fea0641107a1ccee@syzkaller.appspotmail.com
First crash: 2d04h, last: 2d04h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
c24b457b assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in audit_log_start / audit_receive (4) 2026/08/13 00:00 2026/08/13 00:00 2026/08/13 00:34 a56bc0a5
a9d18cc9 assessment-kcsan Benign: ✅ KCSAN: data-race in audit_log_start / audit_receive (4) 2026/08/11 04:13 2026/08/11 04:13 2026/08/11 04:36 039457bd
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in audit_log_start / audit_receive (2) audit 6 8 453d 653d 0/29 auto-obsoleted due to no activity on 2025/07/12 01:35
upstream KCSAN: data-race in audit_log_start / audit_receive (3) prio:high audit 6 21 134d 395d 0/29 auto-obsoleted due to no activity on 2026/05/26 09:19
upstream KCSAN: data-race in audit_log_start / audit_receive kernel 6 1 1710d 1710d 0/29 auto-closed as invalid on 2022/01/10 10:36

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

write to 0xffffffff893dbb98 of 8 bytes by task 18825 on cpu 1:
 audit_ctl_unlock kernel/audit.c:258 [inline]
 audit_receive+0x1d2a/0x1ea0 kernel/audit.c:1627
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x5a7/0x680 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x5be/0x6f0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0x532/0x580 net/socket.c:2684
 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2738
 __sys_sendmsg net/socket.c:2770 [inline]
 __do_sys_sendmsg net/socket.c:2775 [inline]
 __se_sys_sendmsg net/socket.c:2773 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2773
 x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff893dbb98 of 8 bytes by task 18823 on cpu 0:
 audit_ctl_owner_current kernel/audit.c:271 [inline]
 audit_log_start+0x103/0x730 kernel/audit.c:1933
 audit_seccomp+0x49/0x110 kernel/auditsc.c:2948
 seccomp_log kernel/seccomp.c:1048 [inline]
 __seccomp_filter+0x121a/0x1370 kernel/seccomp.c:1376
 __secure_computing+0x7d/0x150 kernel/seccomp.c:1404
 syscall_trace_enter include/linux/entry-common.h:103 [inline]
 syscall_enter_from_user_mode_work include/linux/entry-common.h:147 [inline]
 syscall_enter_from_user_mode include/linux/entry-common.h:178 [inline]
 do_syscall_64+0xd4/0x3c0 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88810210e780 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 18823 Comm: syz.3.3476 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/11 04:13 upstream d58772d8520c 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in audit_log_start / audit_receive
* Struck through repros no longer work on HEAD.