rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=3bf/1/0x4000000000000000 softirq=18371/18371 fqs=6 
	(detected by 0, t=10502 jiffies, g=26477, q=8874)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7257 Comm: syz.0.437 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:div64_u64 include/linux/math64.h:69 [inline]
RIP: 0010:taprio_set_budget net/sched/sch_taprio.c:555 [inline]
RIP: 0010:advance_sched+0x622/0x940 net/sched/sch_taprio.c:761
Code: 65 a0 4c 89 e7 be 08 00 00 00 e8 a9 32 ba f9 4c 89 e0 48 c1 e8 03 42 80 3c 30 00 4c 8b 74 24 50 74 08 4c 89 e7 e8 fe 30 ba f9 <4c> 89 e8 31 d2 49 f7 34 24 49 89 c4 48 89 df be 04 00 00 00 e8 85
RSP: 0018:ffffc90000dd0c80 EFLAGS: 00000046
RAX: 1ffff1100eedb65c RBX: ffff8880604d1b20 RCX: ffffffff88020397
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8880776db2e0
RBP: ffff8880776db340 R08: dffffc0000000000 R09: ffffed100eedb65d
R10: ffffed100eedb65d R11: 1ffff1100eedb65c R12: ffff8880776db2e0
R13: 0000000fa0000000 R14: ffff8880776db000 R15: 188e0cc2d4000000
FS:  00007f6e850dc6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000004fe8c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__sanitizer_cov_trace_pc+0x55/0x60 kernel/kcov.c:214
Code: 2c 8b 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 <48> 89 3a c3 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d 44 a3 8a
RSP: 0018:ffffc90003d77a78 EFLAGS: 00000283
RAX: ffffffff816c2133 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc900057e9000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffc90000e05888 R08: dffffc0000000000 R09: ffffed100ae6fb29
R10: ffffed100ae6fb29 R11: 1ffff1100ae6fb28 R12: ffff88805737d96c
R13: ffff88805737f0c0 R14: ffff88805737d958 R15: dffffc0000000000
 try_to_freeze include/linux/freezer.h:66 [inline]
 freezer_count include/linux/freezer.h:128 [inline]
 freezable_schedule include/linux/freezer.h:173 [inline]
 futex_wait_queue_me+0x273/0x440 kernel/futex/core.c:2863
 futex_wait+0x202/0x5c0 kernel/futex/core.c:2964
 do_futex+0xd1c/0x1240 kernel/futex/core.c:3982
 __do_sys_futex kernel/futex/core.c:4059 [inline]
 __se_sys_futex+0x3a3/0x430 kernel/futex/core.c:4040
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6e86e75749
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:00007f6e850dc0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f6e870cbfa8 RCX: 00007f6e86e75749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6e870cbfa8
RBP: 00007f6e870cbfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6e870cc038 R14: 00007ffc24029a60 R15: 00007ffc24029b48
 </TASK>
rcu: rcu_preempt kthread starved for 10490 jiffies! g26477 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:27680 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 1409 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_single+0x212/0x490 kernel/smp.c:758
Code: 48 44 89 f6 83 e6 01 31 ff e8 ca 5e 0b 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 55 5b 0b 00 e9 a3 00 00 00 f3 90 <f7> 44 24 48 01 00 00 00 0f 84 8e 00 00 00 e8 3b 5b 0b 00 eb e9 e8
RSP: 0018:ffffc900055a75e0 EFLAGS: 00000293
RAX: ffffffff816c70d5 RBX: 0000000000000000 RCX: ffff888023660000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900055a76d0 R08: dffffc0000000000 R09: ffffed1017227681
R10: ffffed1017227681 R11: 1ffff11017227680 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff92000ab4ec0
 rcu_barrier+0x25d/0x4b0 kernel/rcu/tree.c:4082
 br_multicast_dev_del+0x5a7/0x5f0 net/bridge/br_multicast.c:4261
 br_dev_uninit+0x1a/0x70 net/bridge/br_device.c:168
 unregister_netdevice_many+0x131d/0x18f0 net/core/dev.c:11151
 default_device_exit_batch+0x336/0x390 net/core/dev.c:11667
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x77b/0xb80 net/core/net_namespace.c:635
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>