KCSAN: data-race in __mmput / copy

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision
48c467b5	repro		❓	KCSAN: data-race in __mmput / copy_mm (2)	2026/03/07 05:40	2026/03/07 05:40	2026/03/07 05:49	31e9c887
10714081	assessment-kcsan	Benign: ✅ Confident: ✅	❓	KCSAN: data-race in __mmput / copy_mm (2)	2026/01/27 11:25	2026/01/27 11:25	2026/01/27 11:29	b3ce4d18

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __mmput / copy_mm mm	6				1	427d	427d	0/29	auto-obsoleted due to no activity on 2025/08/12 22:58
upstream	KCSAN: data-race in __mmput / copy_mm (3) prio:low mm	6				1	102d	102d	0/29	auto-obsoleted due to no activity on 2026/07/03 14:19

Kernel

Title

Rank 🛈

upstream

KCSAN: data-race in __mmput / copy_mm mm

427d

0/29

auto-obsoleted due to no activity on 2025/08/12 22:58

upstream

KCSAN: data-race in __mmput / copy_mm (3) prio:low mm

102d

0/29

auto-obsoleted due to no activity on 2026/07/03 14:19

================================================================== BUG: KCSAN: data-race in __mmput / copy_mm write to 0xffff8881b9ec37c0 of 8 bytes by task 16274 on cpu 1: __list_del include/linux/list.h:203 [inline] __list_del_entry include/linux/list.h:226 [inline] list_del include/linux/list.h:237 [inline] __mmput+0xe2/0x1c0 kernel/fork.c:1178 mmput+0x40/0x50 kernel/fork.c:1196 exit_mm+0xe3/0x180 kernel/exit.c:581 do_exit+0x3fa/0x1590 kernel/exit.c:959 do_group_exit+0xfe/0x140 kernel/exit.c:1112 get_signal+0xe4f/0xf60 kernel/signal.c:3034 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x6a/0x6f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x1d3/0x2a0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff8881b9ec3600 of 1664 bytes by task 10495 on cpu 0: dup_mm kernel/fork.c:1523 [inline] copy_mm+0xe1/0x370 kernel/fork.c:1581 copy_process+0xcbd/0x1f10 kernel/fork.c:2221 kernel_clone+0x16b/0x5b0 kernel/fork.c:2651 __do_sys_clone kernel/fork.c:2792 [inline] __se_sys_clone kernel/fork.c:2776 [inline] __x64_sys_clone+0x143/0x180 kernel/fork.c:2776 x64_sys_call+0x12d0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:57 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 10495 Comm: syz-executor Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ==================================================================

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/01/27 11:25	upstream	fcb70a56f4d8	9a514c2f	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in __mmput / copy_mm

Crashes (1):

Assets (help?)