INFO: rcu detected stall in sys

Kernel	Title	Rank 🛈	Repro	Cause bisect	Count	Last	Reported	Patched	Status
linux-6.1	INFO: rcu detected stall in sys_newfstat	1			1	38d	38d	0/3	upstream: reported on 2025/12/14 02:05
linux-6.6	INFO: rcu detected stall in sys_newfstat	1			1	211d	211d	0/2	auto-obsoleted due to no activity on 2025/10/02 03:58
linux-5.15	INFO: rcu detected stall in sys_newfstat	1			6	2d07h	226d	0/3	upstream: reported on 2025/06/09 10:15
upstream	INFO: rcu detected stall in sys_newfstat (4) tomoyo	1	C	error	9	4d09h	30d	0/29	upstream: reported C repro on 2025/12/22 03:48
upstream	INFO: rcu detected stall in sys_newfstat mm	1			1	2240d	2240d	0/29	closed as invalid on 2019/12/04 14:04

rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=422/1/0x4000000000000002 softirq=11893/11893 fqs=42 (t=10500 jiffies g=6341 q=176) rcu: rcu_preempt kthread starved for 10413 jiffies! g6341 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28864 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 8379 Comm: udevd Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 </IRQ> RIP: 0010:mod_memcg_page_state+0x16/0x190 include/linux/memcontrol.h:653 Code: 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 54 53 41 89 f6 48 89 fb e8 ba 27 2e 00 <48> 83 c3 38 48 89 d8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df 42 RSP: 0018:ffffc90001ab7938 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff814896c6 RBX: ffffea00023ecf00 RCX: ffff88808f5be240 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00023ecf00 RBP: ffffc90001ab7958 R08: 000000000003a728 R09: ffffed1012d5a731 R10: ffffed1012d5a731 R11: 0000000000000000 R12: ffff8880a4de3da0 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff888096ad3978 free_thread_stack+0x168/0x590 kernel/fork.c:280 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:tomoyo_check_acl+0x10b/0x3a0 security/tomoyo/domain.c:173 Code: 8d 5e 19 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 ea 00 00 00 0f b6 1b 48 8b 55 c8 48 89 d0 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 e9 00 00 00 44 0f b6 3a 0f b6 db 89 df 44 89 fe e8 fc RSP: 0018:ffffc90001ab7bb8 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000 RDX: ffffc90001ab7cb8 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90001ab7c10 R08: ffffffff8360867d R09: ffffffff8360e728 R10: ffff88808f5be240 R11: 0000000000000003 R12: ffff88809a795d00 R13: ffff888094feb410 R14: ffff88809a795d00 R15: dffffc0000000000 tomoyo_path_permission security/tomoyo/file.c:586 [inline] tomoyo_path_perm+0x53e/0x850 security/tomoyo/file.c:838 tomoyo_inode_getattr+0x1c/0x20 security/tomoyo/tomoyo.c:129 security_inode_getattr+0xd5/0x150 security/security.c:1222 vfs_getattr+0x2a/0x6d0 fs/stat.c:115 vfs_statx_fd fs/stat.c:145 [inline] vfs_fstat include/linux/fs.h:3265 [inline] __do_sys_newfstat fs/stat.c:378 [inline] __se_sys_newfstat fs/stat.c:375 [inline] __x64_sys_newfstat+0xa3/0x130 fs/stat.c:375 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fe0c027ccb4 Code: 00 f7 d8 64 89 02 83 c8 ff c3 90 90 90 90 90 90 90 90 90 90 90 90 83 ff 01 89 f0 77 19 48 63 f8 48 89 d6 b8 05 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 18 f3 c3 66 90 48 8b 05 51 51 2b 00 64 c7 00 RSP: 002b:00007ffcc532ccb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000005 RAX: ffffffffffffffda RBX: 0000000001514a00 RCX: 00007fe0c027ccb4 RDX: 00007ffcc532ccc0 RSI: 00007ffcc532ccc0 RDI: 0000000000000005 RBP: 0000000000003fff R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000a R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffcc532d240