rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=82ac/0/0x1 softirq=37341/37349 fqs=0 rcu: (detected by 1, t=10506 jiffies, g=23181, q=170 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:mark_lock+0x7a/0x9f0 kernel/locking/lockdep.c:4732 Code: ff 1f 0f b7 c0 48 0f a3 05 e3 f3 1f 14 0f 83 84 00 00 00 48 8d 04 80 48 8d 04 80 48 8d 04 c5 60 ca b9 95 4c 89 ea 48 23 50 60 01 00 00 00 74 7d 48 8b 54 24 68 65 48 2b 15 5a 1d 19 12 0f 85 RSP: 0018:ffffc90000007b10 EFLAGS: 00000002 RAX: ffffffff95b9ca60 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffff8e098698 RDI: ffffffff8e097b40 RBP: ffffc90000007bb0 R08: 0000000000080000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8e098670 R12: ffffffff8e098698 R13: 0000000000000001 R14: ffffffff8e098698 R15: ffffffff8e097b40 FS: 0000000000000000(0000) GS:ffff8881248f1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000020f030 CR3: 000000007a886000 CR4: 00000000003526f0 Call Trace: mark_usage kernel/locking/lockdep.c:4639 [inline] __lock_acquire+0xc07/0x2890 kernel/locking/lockdep.c:5191 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 __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_activate+0x14c/0x4c0 lib/debugobjects.c:818 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x23/0x380 kernel/time/hrtimer.c:1081 __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0xa31/0xc40 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 16 5f 02 c3 cc cc cc cc 0f 1f 00 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 13 89 11 00 fb f4 4c 33 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6 RAX: 0000000001047a85 RBX: 0000000000000000 RCX: ffffffff8b78d6d9 RDX: 0000000000000000 RSI: ffffffff8dacf385 RDI: ffffffff8bf2b280 RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000 R13: ffffffff8e097b40 R14: ffffffff9088cbd0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3ef/0x4d0 init/main.c:1206 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148 rcu: rcu_preempt kthread starved for 10506 jiffies! g23181 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:27792 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x1138/0x5ee0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6964 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 8604 Comm: syz.2.687 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x70 kernel/kcov.c:217 Code: 8b 05 89 f0 f3 11 a9 00 01 ff 00 74 1d f6 c4 01 74 43 a9 00 00 0f 00 75 3c a9 00 00 f0 00 75 35 8b 82 6c 16 00 00 85 c0 74 2b <8b> 82 48 16 00 00 83 f8 02 75 20 48 8b 8a 50 16 00 00 8b 92 4c 16 RSP: 0018:ffffc90005547a10 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffff8880b84431e0 RCX: ffffffff81b2a071 RDX: ffff88802bd4a4c0 RSI: ffffffff81b2a04b RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: ffff88802bd4aff0 R12: dffffc0000000000 R13: ffffed101708863d R14: 0000000000000001 R15: 0000000000000000 FS: 00007fd90d9d56c0(0000) GS:ffff8881249f1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd90d9d4f98 CR3: 0000000078f83000 CR4: 00000000003526f0 Call Trace: native_pause arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xdfb/0x15e0 kernel/smp.c:877 clock_was_set+0x639/0x860 kernel/time/hrtimer.c:969 do_adjtimex+0x221/0x330 kernel/time/timekeeping.c:2767 do_clock_adjtime kernel/time/posix-timers.c:1161 [inline] __do_sys_clock_adjtime+0x175/0x290 kernel/time/posix-timers.c:1173 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd90f78f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd90d9d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007fd90f9e6090 RCX: 00007fd90f78f749 RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000000 RBP: 00007fd90f813f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd90f9e6128 R14: 00007fd90f9e6090 R15: 00007ffd210af0c8