rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=3344/1/0x4000000000000000 softirq=29334/29336 fqs=0 rcu: (detected by 0, t=10505 jiffies, g=30149, q=544 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 7834 Comm: syz.2.668 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1946 [inline] RIP: 0010:__hrtimer_run_queues+0x738/0xa00 kernel/time/hrtimer.c:1994 Code: 0f 02 00 00 41 0f b6 5c 24 38 31 ff 89 de e8 7f 26 14 00 84 db 0f 85 a9 fa ff ff e8 22 2c 14 00 31 c9 31 d2 48 89 ee 4c 89 e7 33 e3 ff ff e9 90 fa ff ff e8 09 2c 14 00 e8 d4 70 f8 ff 31 ff RSP: 0018:ffffc90000a08e88 EFLAGS: 00000046 RAX: 0000000080010002 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8880b8528600 RDI: ffff88802c619300 RBP: ffff8880b8528600 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88802c619300 R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b8528650 FS: 00007fb34522a6c0(0000) GS:ffff888124470000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000380ce000 CR4: 00000000003526f0 Call Trace: hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 46 f2 56 f6 48 89 df e8 1e 42 57 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 0b 47 f6 65 8b 05 1e 6f 7d 08 85 c0 74 16 5b RSP: 0018:ffffc900066dfc88 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff8880b85284c0 RCX: 0000000000000080 RDX: 0000000000000000 RSI: ffffffff8df21e52 RDI: ffffffff8c1c3800 RBP: 0000000000000287 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: fffffbfff21af82a R13: dffffc0000000000 R14: fcee4fec706dc16b R15: 0000000000000002 class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:571 [inline] clock_was_set+0x5d9/0x870 kernel/time/hrtimer.c:994 do_settimeofday64+0x330/0x4d0 kernel/time/timekeeping.c:1603 do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195 __do_sys_clock_settime kernel/time/posix-timers.c:1124 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1108 [inline] __x64_sys_clock_settime+0x1c1/0x2a0 kernel/time/posix-timers.c:1108 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb34439ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb34522a028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007fb344616270 RCX: 00007fb34439ce59 RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000 RBP: 00007fb344432d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb344616308 R14: 00007fb344616270 R15: 00007ffe52fc87b8 rcu: rcu_preempt kthread starved for 10505 jiffies! g30149 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:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 7833 Comm: syz.3.670 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 39 83 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 RSP: 0018:ffffc9000647f330 EFLAGS: 00000246 RAX: 0000000000080000 RBX: 0000000000000001 RCX: ffffc9001237a000 RDX: 0000000000080000 RSI: ffffffff81fc1ba7 RDI: ffff888027e54a00 RBP: ffff8880b8540f40 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a81e9 R14: 0000000000000001 R15: ffff8880b843c5c0 FS: 00007f34e89f66c0(0000) GS:ffff888124370000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3371fff8 CR3: 000000002a84d000 CR4: 00000000003526f0 DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000081 DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x40/0x90 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+0x45f/0x16f0 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:509 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:499 [inline] tlb_flush_mmu mm/mmu_gather.c:423 [inline] tlb_finish_mmu+0x3fe/0x810 mm/mmu_gather.c:549 unmap_region+0x2d9/0x3b0 mm/vma.c:491 vms_clear_ptes mm/vma.c:1303 [inline] vms_complete_munmap_vmas+0xa4b/0xdd0 mm/vma.c:1345 do_vmi_align_munmap+0x44f/0x5f0 mm/vma.c:1604 do_vmi_munmap+0x1f8/0x3e0 mm/vma.c:1652 do_munmap+0xba/0x100 mm/mmap.c:1067 mremap_to+0x2b3/0x4c0 mm/mremap.c:1448 do_mremap mm/mremap.c:1999 [inline] __do_sys_mremap+0xc42/0x1850 mm/mremap.c:2055 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f34ea79ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f34e89f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000019 RAX: ffffffffffffffda RBX: 00007f34eaa16180 RCX: 00007f34ea79ce59 RDX: 0000000000800000 RSI: 0000000000001000 RDI: 0000200000a96000 RBP: 00007f34ea832d6f R08: 0000200000130000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f34eaa16218 R14: 00007f34eaa16180 R15: 00007fff48daa1c8