rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (4 GPs behind) idle=af44/0/0x1 softirq=24171/24182 fqs=2451 rcu: (detected by 0, t=10502 jiffies, g=11197, q=873 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.17.0-rc1-syzkaller-gdfd4b508c8c6 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:lock_acquire+0xb/0x360 kernel/locking/lockdep.c:5828 Code: 95 c0 c3 cc cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 41 55 <41> 54 53 48 83 ec 60 4d 89 ce 45 89 c7 41 89 cc 89 54 24 04 89 f3 RSP: 0018:ffffc90000a08c70 EFLAGS: 00000046 RAX: 0000000000010002 RBX: ffff8880b8727a80 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880b8727a98 RBP: ffffc90000a08d30 R08: 0000000000000001 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1f47027 R12: ffff88802420e340 R13: dffffc0000000000 R14: 1ffff92000141194 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc58ef7908 CR3: 000000003068c000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:170 __run_hrtimer kernel/time/hrtimer.c:1765 [inline] __hrtimer_run_queues+0x602/0xc60 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:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 13 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 c7 0e 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c2 RAX: 89c2c7953c014900 RBX: ffffffff81968308 RCX: 89c2c7953c014900 RDX: 0000000000000001 RSI: ffffffff8be334e0 RDI: ffffffff81968308 RBP: ffffc90000197f20 R08: ffff8880b8732f9b R09: 1ffff110170e65f3 R10: dffffc0000000000 R11: ffffed10170e65f4 R12: ffffffff8fa38130 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110039d7b40 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147 rcu: rcu_preempt kthread starved for 5600 jiffies! g11197 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:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 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: 0 UID: 0 PID: 5528 Comm: dhcpcd Not tainted 6.17.0-rc1-syzkaller-gdfd4b508c8c6 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b6 62 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 5e 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 45 5e RSP: 0018:ffffc90003517540 EFLAGS: 00000293 RAX: ffffffff81b44d4b RBX: 1ffff110170e7f61 RCX: ffff88802cdf0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900035176c0 R08: ffffffff8fa38137 R09: 1ffffffff1f47026 R10: dffffc0000000000 R11: fffffbfff1f47027 R12: ffff8880b873fb08 R13: dffffc0000000000 R14: ffff8880b863b1c0 R15: 0000000000000001 FS: 00007f7740ee8740(0000) GS:ffff888125c1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555d1965c8 CR3: 0000000032c92000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 __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+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451 dup_mmap+0x15a0/0x1ac0 mm/mmap.c:1873 dup_mm kernel/fork.c:1485 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1537 copy_process+0x1706/0x3c00 kernel/fork.c:2175 kernel_clone+0x21e/0x840 kernel/fork.c:2605 __do_sys_clone kernel/fork.c:2748 [inline] __se_sys_clone kernel/fork.c:2732 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2732 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7740fbc636 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:00007ffe52fcd9a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe52fcd9a8 RCX: 00007f7740fbc636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe52fedef0 R08: 0000000000000000 R09: 0000000000000001 R10: 00007f7740ee8a10 R11: 0000000000000246 R12: 00007ffe52fcdae0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000555e63190ac0