rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=eaa4/1/0x4000000000000000 softirq=28077/28086 fqs=59 rcu: (detected by 1, t=10502 jiffies, g=16757, q=276 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted 6.16.0-rc1-syzkaller-g19272b37aa4f #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x2b/0x80 kernel/locking/spinlock.c:194 Code: 0f 1e fa 55 48 89 f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 16 21 16 f6 48 89 df e8 fe 74 16 f6 f7 c5 00 02 00 00 75 23 9c <58> f6 c4 02 75 37 bf 01 00 00 00 e8 35 95 06 f6 65 8b 05 0e 6a 4a RSP: 0018:ffffc90000007d00 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffffffff9afe8f40 RCX: ffffffff8198cb53 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffffff9afe8f40 RBP: 0000000000000006 R08: 0000000000000000 R09: fffffbfff35fd1e8 R10: ffffffff9afe8f43 R11: ffffffff9afe8f40 R12: 0000000000000002 R13: ffff88805a193340 R14: dffffc0000000000 R15: 1ffff92000000fa8 FS: 0000000000000000(0000) GS:ffff888124754000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbc2ba55e9c CR3: 000000005a87c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_object_activate+0x2ec/0x4c0 lib/debugobjects.c:836 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x23/0x3b0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x8ff/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+0x108/0x3f0 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:debug_lockdep_rcu_enabled+0x20/0x40 kernel/rcu/update.c:320 Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 8b 05 66 5b 28 05 85 c0 74 20 8b 05 60 8c 28 05 85 c0 74 16 65 48 8b 05 28 0e 4d 08 <8b> 80 ec 0a 00 00 85 c0 0f 94 c0 0f b6 c0 c3 cc cc cc cc 66 2e 0f RSP: 0018:ffffc90000147af8 EFLAGS: 00000202 RAX: ffff88801e2bc880 RBX: ffff88801d5b6ed0 RCX: ffffffff822ce9aa RDX: ffff88801e2bc880 RSI: ffffffff822ceb4b RDI: 0000000000000006 RBP: 0000000000000001 R08: 0000000000000006 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000007d601be R13: 0000000000000001 R14: 00000000000357c9 R15: 0000000000000000 rcu_read_unlock include/linux/rcupdate.h:869 [inline] __update_page_owner_free_handle.constprop.0+0x2f0/0x4a0 mm/page_owner.c:283 __reset_page_owner+0x93/0x1a0 mm/page_owner.c:309 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706 pagetable_free include/linux/mm.h:2879 [inline] pagetable_dtor_free include/linux/mm.h:2977 [inline] __tlb_remove_table include/asm-generic/tlb.h:220 [inline] __tlb_remove_table_free mm/mmu_gather.c:227 [inline] tlb_remove_table_rcu+0x116/0x1a0 mm/mmu_gather.c:290 rcu_do_batch kernel/rcu/tree.c:2576 [inline] rcu_core+0x79c/0x14e0 kernel/rcu/tree.c:2832 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579 run_ksoftirqd kernel/softirq.c:968 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960 smpboot_thread_fn+0x3f7/0xae0 kernel/smpboot.c:164 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10205 jiffies! g16757 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:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 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+0x5d4/0x6f0 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: 6518 Comm: udevd Not tainted 6.16.0-rc1-syzkaller-g19272b37aa4f #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x18/0x90 kernel/kcov.c:246 Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 d7 a9 10 12 65 8b 05 e8 a9 10 12 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 0f 00 75 60 a9 00 00 RSP: 0018:ffffc9000427f6e0 EFLAGS: 00000202 RAX: 0000000000000002 RBX: ffff8880b8443ba0 RCX: ffffffff81b0011d RDX: ffff888078da4880 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed1017088775 R15: ffff8880b853cf40 FS: 00007f40e5074880(0000) GS:ffff888124854000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564177f37c00 CR3: 000000004ae35000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0xd9d/0x1510 kernel/smp.c:885 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 vms_clear_ptes+0x55e/0x770 mm/vma.c:1244 vms_complete_munmap_vmas+0x1ca/0x970 mm/vma.c:1286 do_vmi_align_munmap+0x43b/0x7d0 mm/vma.c:1545 do_vmi_munmap+0x204/0x3e0 mm/vma.c:1593 __vm_munmap+0x19a/0x390 mm/vma.c:3122 __do_sys_munmap mm/mmap.c:1084 [inline] __se_sys_munmap mm/mmap.c:1081 [inline] __x64_sys_munmap+0x59/0x80 mm/mmap.c:1081 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: 0033:0x7f40e491e097 Code: 73 01 c3 48 8b 0d 61 2d 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 2d 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ffd7f0169d8 EFLAGS: 00000206 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000564177cd6f90 RCX: 00007f40e491e097 RDX: 0000000000000000 RSI: 00000000009480e8 RDI: 00007f40e3c00000 RBP: 0000564177cd42c0 R08: 0000564177f14620 R09: 0000000000000006 R10: 0000000000000000 R11: 0000000000000206 R12: 0000564147c41588 R13: 00007ffd7f016a60 R14: 0000000000000000 R15: 0000000000000000