KCSAN: data-race in css_set_move_task / memcpy_and

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
a62d892f-d195-4269-accc-2785bf5ee2e6	assessment-security	DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	KCSAN: data-race in css_set_move_task / memcpy_and_pad (2)	2026/05/26 15:09	2026/05/26 15:09	2026/05/26 15:49	76d4b4b1b168407cf701ec594f642e93a00ce699
289c7d69-5ffc-4fbf-a48b-54cf0f19290f	assessment-kcsan	Benign: ✅ Confident: ✅	❓	KCSAN: data-race in css_set_move_task / memcpy_and_pad (2)	2026/02/25 03:58	2026/02/25 03:58	2026/02/25 04:16	305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
2164efd1-9592-45e7-9497-d5274392ba36	assessment-kcsan		💥	KCSAN: data-race in css_set_move_task / memcpy_and_pad (2)	2026/01/23 07:56	2026/01/23 07:56	2026/01/23 07:56	499a21815ec0ab13dbfc80e05fc32aadbc482145	failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "16" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/usr/local/google/home/dvyukov/syzkaller/wo... truncated to first 200 bytes; open job for full error

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in css_set_move_task / memcpy_and_pad cgroups	6				1	391d	391d	0/29	auto-obsoleted due to no activity on 2025/07/24 11:25

Kernel

Title

Rank 🛈

upstream

KCSAN: data-race in css_set_move_task / memcpy_and_pad cgroups

391d

0/29

auto-obsoleted due to no activity on 2025/07/24 11:25

================================================================== BUG: KCSAN: data-race in css_set_move_task / memcpy_and_pad write to 0xffff8881042fbbc8 of 8 bytes by task 17 on cpu 1: __list_del include/linux/list.h:203 [inline] __list_del_entry include/linux/list.h:226 [inline] list_del_init include/linux/list.h:295 [inline] css_set_move_task+0x212/0x430 kernel/cgroup/cgroup.c:932 do_cgroup_task_dead kernel/cgroup/cgroup.c:7082 [inline] cgroup_task_dead+0x74/0x340 kernel/cgroup/cgroup.c:7151 finish_task_switch+0x1b5/0x280 kernel/sched/core.c:5193 context_switch kernel/sched/core.c:5301 [inline] __schedule+0x93c/0xd40 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x5e/0xd0 kernel/sched/core.c:7008 schedule_timeout+0xca/0x180 kernel/time/sleep_timeout.c:99 synchronize_rcu_expedited_wait_once kernel/rcu/tree_exp.h:545 [inline] synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:663 [inline] rcu_exp_wait_wake kernel/rcu/tree_exp.h:692 [inline] rcu_exp_sel_wait_wake+0x590/0xbe0 kernel/rcu/tree_exp.h:726 wait_rcu_exp_gp+0x1e/0x30 kernel/rcu/tree_exp.h:492 kthread_worker_fn+0x262/0x540 kernel/kthread.c:1025 kthread+0x22a/0x280 kernel/kthread.c:436 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read to 0xffff8881042fb240 of 3328 bytes by task 4512 on cpu 0: memcpy_and_pad+0x48/0x80 lib/string_helpers.c:1008 arch_dup_task_struct+0x2c/0x40 arch/x86/kernel/process.c:108 dup_task_struct+0x6e/0x950 kernel/fork.c:920 copy_process+0x37e/0x20b0 kernel/fork.c:2050 kernel_clone+0x16b/0x5d0 kernel/fork.c:2653 __do_sys_clone kernel/fork.c:2794 [inline] __se_sys_clone kernel/fork.c:2778 [inline] __x64_sys_clone+0x143/0x180 kernel/fork.c:2778 x64_sys_call+0x1222/0x3020 arch/x86/include/generated/asm/syscalls_64.h:57 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x370 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: 4512 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 ==================================================================

Crashes (6):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Assets (help?)	Manager	Title
2026/04/02 13:33	upstream	9147566d8016	91bc79b0	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in css_set_move_task / memcpy_and_pad
2026/02/16 00:59	upstream	26a4cfaff82a	1e62d198	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in css_set_move_task / memcpy_and_pad
2026/02/04 18:27	upstream	5fd0a1df5d05	ea10c935	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in css_set_move_task / memcpy_and_pad
2026/02/02 01:17	upstream	9f2693489ef8	6b8752f2	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in css_set_move_task / memcpy_and_pad
2026/01/22 19:39	upstream	a66191c590b3	82c9c083	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in css_set_move_task / memcpy_and_pad
2026/01/20 10:41	upstream	24d479d26b25	06648d9c	.config	console log	report	info	[disk image] [vmlinux] [kernel image]	ci2-upstream-kcsan-gce	KCSAN: data-race in css_set_move_task / memcpy_and_pad

Crashes (6):

Assets (help?)