rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10506 jiffies, g=163049, q=509 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10506 (4295021540-4295011034), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10506 jiffies! g163049 f0x2 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:28904 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 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
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5728 Comm: kworker/1:5 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events nsim_fib_event_work
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:222 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:233 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:649 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:1231 [inline]
RIP: 0010:trace_hrtimer_expire_exit include/trace/events/timer.h:308 [inline]
RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1933 [inline]
RIP: 0010:__hrtimer_run_queues+0x198/0xa00 kernel/time/hrtimer.c:1994
Code: f4 06 00 00 e8 d9 32 14 00 4c 89 e8 be 08 00 00 00 48 c1 e8 06 48 8d 3c c5 50 e9 d7 90 e8 90 fe 81 00 4c 0f a3 2d 28 6a e3 0e <41> 0f 92 c5 31 ff 44 89 ee e8 fa 2c 14 00 45 84 ed 0f 85 93 05 00
RSP: 0018:ffffc90000a08e88 EFLAGS: 00000047
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81f47f20
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff90d7e950
RBP: ffff8880b8528600 R08: 0000000000000000 R09: fffffbfff21afd2a
R10: ffffffff90d7e957 R11: 0000000000000001 R12: ffff888041125300
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b8528650
FS:  0000000000000000(0000) GS:ffff88812446a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb0a3fd5d58 CR3: 0000000034067000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000000fd
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:__timer_delete_sync+0x7d/0x1c0 kernel/time/timer.c:1611
Code: a7 f0 ff 4c 89 ee 48 89 df e8 6f ac f0 ff 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 ed c5 14 00 58 48 85 db 0f 85 15 01 00 00 <e8> fe ca 14 00 65 8b 1d 47 79 17 12 31 ff 81 e3 00 00 0f 00 89 de
RSP: 0018:ffffc900045ff988 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81f3e7e1
RDX: ffff888027f50000 RSI: ffffffff81f3e7ec RDI: ffff888027f50000
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc900045ff9d0
R13: ffffffff81f3e7b1 R14: ffff888027f50000 R15: dffffc0000000000
 schedule_timeout+0x12f/0x280 kernel/time/sleep_timeout.c:100
 msleep+0x32/0x50 kernel/time/sleep_timeout.c:318
 nsim_fib6_rt_add drivers/net/netdevsim/fib.c:693 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:759 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x490a/0x63b0 drivers/net/netdevsim/fib.c:1493
 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 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
 </TASK>