rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=d944/1/0x4000000000000000 softirq=58033/58034 fqs=0 rcu: (detected by 1, t=10506 jiffies, g=50025, q=335 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16853 Comm: syz.4.2892 Not tainted 6.16.0-rc1-syzkaller-00157-g02adc1490e6d #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:IS_ERR include/linux/err.h:70 [inline] RIP: 0010:debug_object_activate+0x1fd/0x420 lib/debugobjects.c:825 Code: 00 74 08 48 89 ef e8 d2 21 61 fd 48 8b 55 00 48 39 d3 0f 92 c0 48 8d 8a 00 80 00 00 48 39 cb 0f 93 c1 08 c1 0f 84 10 01 00 00 <49> 81 fd 00 f0 ff ff 77 45 49 8d 6d 10 49 89 ef 49 c1 ef 03 43 0f RSP: 0018:ffffc90000007c88 EFLAGS: 00000046 RAX: 1ffff1100f37c62d RBX: ffff88802851b340 RCX: dffffc0000000000 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000007b60 RBP: ffffffff99c58690 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f6c R12: ffff888079be3168 R13: ffff888079be3150 R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125c84000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001640 CR3: 000000005c6c2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216 Code: 8b 3d f4 e5 f8 0b 48 89 de 5b e9 33 86 56 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 08 c0 99 92 65 8b 15 d8 71 d9 10 81 e2 00 01 ff 00 RSP: 0018:ffffc90003f0faa0 EFLAGS: 00000202 RAX: ffffffff82423cc9 RBX: ffff8880353b6c00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff RBP: 1ffff1100b0774e0 R08: ffff8880583ba7d3 R09: 1ffff1100b0774fa R10: dffffc0000000000 R11: ffffed100b0774fb R12: 0000000000000001 R13: dffffc0000000000 R14: ffff8880583ba7d0 R15: ffff8880353b6c08 exit_fs+0xb9/0x150 fs/fs_struct.c:107 do_exit+0x6a0/0x22e0 kernel/exit.c:951 do_group_exit+0x21c/0x2d0 kernel/exit.c:1104 get_signal+0x125e/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3cb4f8e929 Code: Unable to access opcode bytes at 0x7f3cb4f8e8ff. RSP: 002b:00007f3cb5e580e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f3cb51b5fa8 RCX: 00007f3cb4f8e929 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3cb51b5fa8 RBP: 00007f3cb51b5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3cb51b5fac R13: 0000000000000000 R14: 00007fff8aaa83d0 R15: 00007fff8aaa84b8 rcu: rcu_preempt kthread starved for 10506 jiffies! g50025 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 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: 5994 Comm: kworker/u8:30 Not tainted 6.16.0-rc1-syzkaller-00157-g02adc1490e6d #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf69/0x12d0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 50 78 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 fb 73 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 e0 73 0b RSP: 0018:ffffc9000495f6a0 EFLAGS: 00000293 RAX: ffffffff81b4da60 RBX: ffff8880b873c9c0 RCX: ffff888030db5a00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000495f800 R08: ffffffff8f9fe5f7 R09: 1ffffffff1f3fcbe R10: dffffc0000000000 R11: fffffbfff1f3fcbf R12: 1ffff110170c868d R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8643468 FS: 0000000000000000(0000) GS:ffff888125d84000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9474381178 CR3: 000000000df38000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2660 [inline] smp_text_poke_batch_finish+0x5e0/0x1100 arch/x86/kernel/alternative.c:2870 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245