rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6870/1:b..l
	(detected by 1, t=10502 jiffies, g=18753, q=259)
task:syz.6.641       state:R  running task     stack:21984 pid: 6870 ppid:  5303 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6552
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6577
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __local_bh_enable_ip+0x13b/0x1b0 kernel/softirq.c:408
 spin_unlock_bh include/linux/spinlock.h:408 [inline]
 sctp_inet6addr_event+0x67d/0x730 net/sctp/ipv6.c:113
 notifier_call_chain kernel/notifier.c:83 [inline]
 atomic_notifier_call_chain+0x15d/0x280 kernel/notifier.c:198
 addrconf_ifdown+0xdf4/0x1970 net/ipv6/addrconf.c:3906
 addrconf_notify+0x445/0xf00 net/ipv6/addrconf.c:-1
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_extack net/core/dev.c:2061 [inline]
 call_netdevice_notifiers net/core/dev.c:2075 [inline]
 dev_close_many+0x28d/0x400 net/core/dev.c:1650
 unregister_netdevice_many+0x472/0x18f0 net/core/dev.c:11110
 rtnl_delete_link net/core/rtnetlink.c:3112 [inline]
 rtnl_dellink+0x3db/0x700 net/core/rtnetlink.c:3163
 rtnetlink_rcv_msg+0x9b9/0xe60 net/core/rtnetlink.c:5650
 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2489
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x77c/0x920 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg+0x190/0x250 net/socket.c:2526
 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: 0033:0x7f451da4e929
RSP: 002b:00007f451b8b6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f451dc75fa0 RCX: 00007f451da4e929
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000000000000008
RBP: 00007f451dad0b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f451dc75fa0 R15: 00007ffefb946398
 </TASK>
rcu: rcu_preempt kthread starved for 9360 jiffies! g18753 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:27584 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 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 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:3932 [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:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 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:default_idle+0xb/0x10 arch/x86/kernel/process.c:723
Code: bf 48 89 df e8 26 8c 12 f8 eb b5 e8 3f be f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d 97 13 5b 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffc90000d67d48 EFLAGS: 000002c2
RAX: 9da7ed124ffe6e00 RBX: ffff88813fe48000 RCX: 9da7ed124ffe6e00
RDX: 0000000000000001 RSI: ffffffff8a0b11c0 RDI: ffffffff8a59a740
RBP: ffffc90000d67e80 R08: dffffc0000000000 R09: ffffed101722765a
R10: ffffed101722765a R11: 1ffff11017227659 R12: ffffffff8d68abe8
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11027fc9000
 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:194 [inline]
 do_idle+0x21b/0x5b0 kernel/sched/idle.c:306
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
 start_secondary+0x31f/0x430 arch/x86/kernel/smpboot.c:281
 secondary_startup_64_no_verify+0xb1/0xbb
 </TASK>