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			4	9d11h	162d	0/3	upstream: reported on 2025/12/14 02:05
linux-6.6	INFO: rcu detected stall in sys_newfstat (2)	1			3	2d02h	46d	0/2	upstream: reported on 2026/04/09 12:06
linux-6.6	INFO: rcu detected stall in sys_newfstat	1			1	335d	335d	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			9	20h35m	350d	0/3	upstream: reported on 2025/06/09 10:15
upstream	INFO: rcu detected stall in sys_newfstat (4) prio:low mm	1	C	error	26	9h06m	154d	0/29	upstream: reported C repro on 2025/12/22 03:48
upstream	INFO: rcu detected stall in sys_newfstat (2) mm	1			1	2329d	2329d	0/29	closed as invalid on 2020/01/08 05:33

rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=61e/1/0x4000000000000002 softirq=11256/11258 fqs=32 (t=10500 jiffies g=6989 q=217) rcu: rcu_preempt kthread starved for 10433 jiffies! g6989 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 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: 4165 Comm: udevd Not tainted 5.4.0-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:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 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:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:98 Code: 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 53 48 89 fb e8 13 00 00 00 48 8b 3d 74 25 cd 07 48 89 de e8 64 02 3b 00 5b 5d c3 cc <48> 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 b8 81 8b 7e f7 c2 RSP: 0018:ffffc90001dc78e0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff1101188f921 RBX: ffffea00028d5dc0 RCX: ffff8880a004a500 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00028d5dc0 RBP: ffffc90001dc7920 R08: dffffc0000000000 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff88808c47c9a0 R13: dffffc0000000000 R14: 1ffff1101188f934 R15: ffff8880a92dba28 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_path_matches_pattern+0x5d/0x280 security/tomoyo/util.c:918 Code: 08 4c 89 e7 e8 34 73 5b fe 49 8b 04 24 48 89 45 c8 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 16 73 5b fe 49 8b 07 <48> 89 45 d0 49 8d 7f 0c 48 89 f8 48 c1 e8 03 42 8a 04 28 84 c0 0f RSP: 0018:ffffc90001dc7b30 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff02 RAX: ffff888094f21da8 RBX: 1ffff11014023e84 RCX: ffff8880a004a500 RDX: 0000000000000000 RSI: ffff888094f21d98 RDI: ffffc90001dc7c60 RBP: ffffc90001dc7b70 R08: ffffffff835564ea R09: ffffffff83557a68 R10: ffff8880a004a500 R11: 0000000000000003 R12: ffffc90001dc7c60 R13: dffffc0000000000 R14: ffff8880a011f420 R15: ffff888094f21d98 tomoyo_compare_name_union security/tomoyo/file.c:87 [inline] tomoyo_check_path_acl+0xf2/0x180 security/tomoyo/file.c:260 tomoyo_check_acl+0x133/0x3a0 security/tomoyo/domain.c:172 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: 0033:0x7f7ae06a5cb4 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:00007fff4e435b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000005 RAX: ffffffffffffffda RBX: 0000000001da5930 RCX: 00007f7ae06a5cb4 RDX: 00007fff4e435b30 RSI: 00007fff4e435b30 RDI: 0000000000000005 RBP: 00000000ffffffff R08: 00007f7ae0f9e7a0 R09: 00007f7ae0f9e7a0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000420724 R13: 0000000000000002 R14: 0000000000420724 R15: 0000000000420724