syzbot


KCSAN: data-race in copy_creds / prepare_creds (3)

Status: moderation: reported on 2026/06/23 14:40
Subsystems: lsm
Labels: race:benign prio:low
[Documentation on labels]
Reported-by: syzbot+5227aabe7c8960628bea@syzkaller.appspotmail.com
First crash: 1d12h, last: 1d12h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
75eb4387-642b-409a-99bc-a91ef4a28159 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in copy_creds / prepare_creds (3) 2026/06/25 00:00 2026/06/25 00:00 2026/06/25 00:13 2e5297c5126f27e51eeef9157f2111c5beb11e4f

			
		
87611e02-527d-4044-b441-00ff0adc5e55 assessment-kcsan Benign: ✅ KCSAN: data-race in copy_creds / prepare_creds (3) 2026/06/23 14:39 2026/06/23 14:39 2026/06/23 15:05 e30e5c89d137d970da183ffdc275130a55fdd832

			
		
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in copy_creds / prepare_creds lsm 6 3 263d 282d 0/29 auto-obsoleted due to no activity on 2025/11/29 06:24
upstream KCSAN: data-race in copy_creds / prepare_creds (2) lsm prio:high 6 8 90d 205d 0/29 auto-obsoleted due to no activity on 2026/05/21 11:07

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

write to 0xffff888103fc6b28 of 4 bytes by task 9782 on cpu 0:
 get_cred_many include/linux/cred.h:222 [inline]
 copy_creds+0x78/0x340 kernel/cred.c:278
 copy_process+0x8b8/0x2350 kernel/fork.c:2148
 kernel_clone+0x1c0/0x5f0 kernel/fork.c:2746
 __do_sys_clone3 kernel/fork.c:3048 [inline]
 __se_sys_clone3+0x1f5/0x230 kernel/fork.c:3027
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:3027
 x64_sys_call+0x580/0x3020 arch/x86/include/generated/asm/syscalls_64.h:436
 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 0xffff888103fc6a80 of 184 bytes by task 9783 on cpu 1:
 prepare_creds+0x71/0x550 kernel/cred.c:192
 __do_sys_capset kernel/capability.c:247 [inline]
 __se_sys_capset+0x2da/0x480 kernel/capability.c:216
 __x64_sys_capset+0x31/0x40 kernel/capability.c:216
 x64_sys_call+0x2aac/0x3020 arch/x86/include/generated/asm/syscalls_64.h:127
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 9783 Comm: syz.5.1734 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/23 14:39 upstream 502d801f0ab0 4b1d8f01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_creds / prepare_creds
* Struck through repros no longer work on HEAD.