rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=ec7c/1/0x4000000000000000 softirq=67523/67523 fqs=2 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5757/1:b..l rcu: (detected by 0, t=10502 jiffies, g=74161, q=559 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 12603 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:instrument_read_write include/linux/instrumented.h:55 [inline] RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1301 [inline] RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] RIP: 0010:do_raw_spin_lock+0x121/0x2f0 kernel/locking/spinlock_debug.c:116 Code: c8 0f 84 2b 01 00 00 41 c6 44 14 04 04 c7 44 24 40 00 00 00 00 48 89 df be 04 00 00 00 49 89 d6 e8 34 39 91 00 48 8d 7c 24 40 04 00 00 00 e8 25 39 91 00 8b 44 24 40 b9 01 00 00 00 f0 0f b1 RSP: 0018:ffffc90000a08d20 EFLAGS: 00000056 RAX: 00000000ffffff01 RBX: ffff8880b87281c0 RCX: ffffffff81a2c67c RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000a08d60 RBP: ffffc90000a08dc8 R08: ffff8880b87281c3 R09: 1ffff110170e5038 R10: dffffc0000000000 R11: ffffed10170e5039 R12: 1ffff920001411a8 R13: ffff8880b87281c8 R14: dffffc0000000000 R15: 1ffff110170e5039 FS: 000055558eca4500(0000) GS:ffff888125059000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6ba3b03000 CR3: 000000005e426000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __run_hrtimer kernel/time/hrtimer.c:2036 [inline] __hrtimer_run_queues+0x466/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__fsnotify_parent+0xeb/0x620 fs/notify/fsnotify.c:189 Code: ff 4c 89 f0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 f7 e8 89 2c d7 ff 41 bf f0 00 00 00 4d 03 3e 4c 89 f8 48 c1 e8 03 0f b6 04 18 <84> c0 0f 85 9d 04 00 00 41 8b 07 89 44 24 30 4c 8b 7c 24 28 eb 36 RSP: 0018:ffffc90003167b60 EFLAGS: 00000212 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88802d348000 RDX: 0000000000000000 RSI: ffffffff8ecefa00 RDI: 0000000000000002 RBP: ffffc90003167c90 R08: ffff88802d348000 R09: 0000000000000002 R10: 0000000000000002 R11: 0000000000000000 R12: 1ffff9200062cfa0 R13: 0000000000000002 R14: ffff888053046400 R15: ffff888060c6ded0 fsnotify_parent include/linux/fsnotify.h:96 [inline] fsnotify_path include/linux/fsnotify.h:113 [inline] fsnotify_file include/linux/fsnotify.h:127 [inline] fsnotify_access include/linux/fsnotify.h:429 [inline] vfs_read+0x865/0xa80 fs/read_write.c:578 ksys_read+0x150/0x270 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0a3d35e68e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007ffcf2d6fc08 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000055558eca4500 RCX: 00007f0a3d35e68e RDX: 00000000000003e8 RSI: 00007ffcf2d6fc70 RDI: 00000000000000c8 RBP: 00007ffcf2d700ac R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000170 R13: 00000000000927c0 R14: 000000000009be7a R15: 00007ffcf2d70100 task:kworker/1:5 state:R running task stack:21392 pid:5757 tgid:5757 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_power_efficient gc_worker Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline] RIP: 0010:rcu_is_watching+0x9/0xb0 kernel/rcu/tree.c:751 Code: 64 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 <65> ff 05 10 22 c1 11 e8 db 73 23 0a 89 c3 83 f8 08 73 65 49 bf 00 RSP: 0018:ffffc90002d978e0 EFLAGS: 00000297 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8eb59c60 RBP: ffffffff89f04584 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff20aedff R12: 0000000000000002 R13: ffffffff8eb59c60 R14: 0000000000000000 R15: 0000000000000000 trace_lock_acquire include/trace/events/lock.h:23 [inline] lock_acquire+0x5f/0x350 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] gc_worker+0x298/0x1890 net/netfilter/nf_conntrack_core.c:1532 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10498 jiffies! g74161 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 12580 Comm: dhcpcd-run-hook Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x10b5/0x14b0 kernel/smp.c:892 Code: 1e 89 de 83 e6 01 31 ff e8 d8 1e 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 84 1a 0c 00 eb 37 f3 90 41 0f b6 04 1c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 69 1a 0c 00 eb e5 44 89 RSP: 0018:ffffc90003d17580 EFLAGS: 00000293 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888028ee1f00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003d176a8 R08: ffffffff90576ff7 R09: 1ffffffff20aedfe R10: dffffc0000000000 R11: fffffbfff20aedff R12: 1ffff110170e81d1 R13: ffff8880b863c448 R14: ffff8880b8740e88 R15: 0000000000000001 FS: 00007f61d9691c80(0000) GS:ffff888124f59000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560f5e234048 CR3: 000000007fe58000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c4/0x1090 arch/x86/mm/tlb.c:1451 dup_mmap+0x1786/0x1d90 mm/mmap.c:1905 dup_mm kernel/fork.c:1543 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1595 copy_process+0x1e3e/0x4390 kernel/fork.c:2289 kernel_clone+0x2d7/0x940 kernel/fork.c:2748 __do_sys_clone kernel/fork.c:2889 [inline] __se_sys_clone kernel/fork.c:2873 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2873 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f61d982b636 Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffe4aede1c0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe4aede1c8 RCX: 00007f61d982b636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000560f5e223e60 R08: 0000000000000000 R09: 0000560f5e223c30 R10: 00007f61d9691f50 R11: 0000000000000246 R12: 0000560f5e227b40 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000