rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=5624/1/0x4000000000000000 softirq=18491/18493 fqs=0 rcu: (detected by 1, t=11541 jiffies, g=9993, q=446 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5974 Comm: udevd Not tainted 6.16.0-rc5-syzkaller-00193-g40f92e79b0aa #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:hlock_class+0x13/0x70 kernel/locking/lockdep.c:234 Code: 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f b7 47 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 fd 58 3f 14 <73> 15 48 8d 04 80 48 8d 04 80 48 8d 04 c5 20 79 d7 95 c3 cc cc cc RSP: 0018:ffffc90000007bf0 EFLAGS: 00000047 RAX: 0000000000000000 RBX: 0000000000000002 RCX: 000000002f227b48 RDX: 0000000000000000 RSI: 00000000c101d9ab RDI: ffff88802c258b40 RBP: ffff88802c258000 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88802c258af0 R13: ffff88802c258b40 R14: 0000000000000002 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff888124715000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e7bef6abe0 CR3: 000000000e382000 CR4: 00000000003526f0 Call Trace: __lock_acquire+0x622/0x1c90 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 debug_object_deactivate+0x135/0x3a0 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x46f/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xd7b/0x1510 kernel/smp.c:885 Code: e8 6a 19 0c 00 45 85 ed 74 46 48 8b 14 24 49 89 d6 49 89 d5 49 c1 ee 03 41 83 e5 07 4d 01 e6 41 83 c5 03 e8 07 1e 0c 00 f3 90 <41> 0f b6 06 41 38 c5 7c 08 84 c0 0f 85 6f 05 00 00 8b 43 08 31 ff RSP: 0018:ffffc9000399f948 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b853fe20 RCX: ffffffff81afd92d RDX: ffff88802c258000 RSI: ffffffff81afd909 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed10170a7fc5 R15: ffff8880b843b580 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x4a0/0x1790 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline] tlb_flush_mmu mm/mmu_gather.c:403 [inline] tlb_finish_mmu+0x3c9/0x7c0 mm/mmu_gather.c:497 exit_mmap+0x403/0xb90 mm/mmap.c:1297 __mmput+0x12a/0x410 kernel/fork.c:1121 mmput+0x62/0x70 kernel/fork.c:1144 exit_mm kernel/exit.c:581 [inline] do_exit+0x7c4/0x2bd0 kernel/exit.c:952 do_group_exit+0xd3/0x2a0 kernel/exit.c:1105 __do_sys_exit_group kernel/exit.c:1116 [inline] __se_sys_exit_group kernel/exit.c:1114 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1114 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1888af16c5 Code: Unable to access opcode bytes at 0x7f1888af169b. RSP: 002b:00007fffd8dad968 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000055e7bef71060 RCX: 00007f1888af16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 000055e7bed302c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffd8dad9b0 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 11541 jiffies! g9993 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5401 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6790 __schedule_loop kernel/sched/core.c:6868 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6883 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 6040 Comm: kworker/1:6 Not tainted 6.16.0-rc5-syzkaller-00193-g40f92e79b0aa #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_power_efficient gc_worker RIP: 0010:__seqprop_spinlock_sequence include/linux/seqlock.h:227 [inline] RIP: 0010:nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:333 [inline] RIP: 0010:gc_worker+0x2d5/0x16e0 net/netfilter/nf_conntrack_core.c:1537 Code: 00 00 48 c7 c7 88 31 aa 90 e8 a7 ad eb f7 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 25 18 0f f8 58 48 85 db 0f 85 d4 0f 00 00 a6 1c 0f f8 8b 1d 10 57 fd 06 41 89 dc 31 ff 41 83 e4 01 44 89 RSP: 0018:ffffc900030d7b58 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff89ace5a9 RDX: ffff888030fca440 RSI: ffffffff89ace5b8 RDI: 0000000000000007 RBP: ffffffff9b27aecc R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff888031c00000 R13: 0000000000040000 R14: dffffc0000000000 R15: 0000000000001770 FS: 0000000000000000(0000) GS:ffff888124815000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000600 CR3: 0000000076840000 CR4: 00000000003526f0 Call Trace: process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245