rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (2 GPs behind) idle=5024/1/0x4000000000000000 softirq=32550/32551 fqs=6
rcu: 	(detected by 0, t=10502 jiffies, g=29709, q=637 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10152 Comm: syz.0.1195 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:rb_insert_color+0x5/0x680 lib/rbtree.c:435
Code: 5c 41 5d 41 5e 41 5f 5d 41 ff e3 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 28 49 89 f7 49 89 fc 49 be 00
RSP: 0018:ffffc90000a08ce0 EFLAGS: 00000086
RAX: 1ffff110170e508b RBX: 1ffff110170e508a RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880b8728450 RDI: ffff88804fa12300
RBP: 0000000000000001 R08: ffff88804fa12317 R09: 0000000000000000
R10: ffff88804fa12300 R11: ffffed1009f42463 R12: ffff88804fa12300
R13: dffffc0000000000 R14: ffff8880b8728450 R15: ffff8880b8728458
FS:  00007f69198836c0(0000) GS:ffff888125566000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f39f35e4ff8 CR3: 000000007a68a000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rb_insert_color_cached include/linux/rbtree.h:142 [inline]
 rb_add_cached include/linux/rbtree.h:211 [inline]
 timerqueue_add+0x1d0/0x200 lib/timerqueue.c:40
 __run_hrtimer kernel/time/hrtimer.c:1802 [inline]
 __hrtimer_run_queues+0x650/0xcc0 kernel/time/hrtimer.c:1849
 hrtimer_interrupt+0x42b/0x1010 kernel/time/hrtimer.c:1911
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x460 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lockdep_unregister_key+0x2d5/0x350 kernel/locking/lockdep.c:6616
Code: 51 0c 09 00 89 c6 48 c7 c7 d0 f8 23 96 e8 93 07 0e 0a 90 e9 65 fe ff ff e8 f8 52 0b 0a 41 f7 c7 00 02 00 00 74 b3 fb 40 84 ed <75> b2 eb c3 90 0f 0b 90 e9 26 ff ff ff 90 0f 0b 90 e9 2e ff ff ff
RSP: 0018:ffffc900061b7090 EFLAGS: 00000246
RAX: 0000000000000046 RBX: ffff88802a384268 RCX: 0000000000000046
RDX: ffffffff93df7438 RSI: ffffffff8df0b19b RDI: ffffffff8c27a480
RBP: ffff888076cebc00 R08: ffffffff81aef2d8 R09: ffffffff8e7602e0
R10: dffffc0000000000 R11: fffffbfff2022e57 R12: 0000000000000000
R13: ffff88802a384269 R14: 0000000000001000 R15: 0000000000000a87
 qdisc_lock_uninit include/net/pkt_sched.h:332 [inline]
 __qdisc_destroy+0x1ab/0x4a0 net/sched/sch_generic.c:1077
 taprio_attach+0x25a/0x380 net/sched/sch_taprio.c:2161
 qdisc_graft+0x11b4/0x15b0 net/sched/sch_api.c:1162
 __tc_modify_qdisc net/sched/sch_api.c:1761 [inline]
 tc_modify_qdisc+0x18a4/0x2290 net/sched/sch_api.c:1817
 rtnetlink_rcv_msg+0x77e/0xbe0 net/core/rtnetlink.c:6967
 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa68/0xad0 net/socket.c:2592
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2683 [inline]
 __se_sys_sendmsg net/socket.c:2681 [inline]
 __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f691899c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6919883028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f6918c16090 RCX: 00007f691899c629
RDX: 0000000000000000 RSI: 00002000000012c0 RDI: 0000000000000006
RBP: 00007f6918a32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6918c16128 R14: 00007f6918c16090 R15: 00007ffcac68e3b8
 </TASK>
rcu: rcu_preempt kthread starved for 10490 jiffies! g29709 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:28128 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1585/0x5340 kernel/sched/core.c:6907
 __schedule_loop kernel/sched/core.c:6989 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7004
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 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:
CPU: 0 UID: 0 PID: 5820 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcea/0x12c0 kernel/smp.c:877
Code: 89 ee 83 e6 01 31 ff e8 24 e3 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 cf de 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 b3 de 0b 00 eb e4 44
RSP: 0000:ffffc90003ad7820 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff110170e812d RCX: ffff888032d2bc80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003ad7950 R08: ffffffff901172b7 R09: 1ffffffff2022e56
R10: dffffc0000000000 R11: fffffbfff2022e57 R12: ffff8880b8740968
R13: dffffc0000000000 R14: ffff8880b863bf80 R15: 0000000000000001
FS:  000055555e2c0500(0000) GS:ffff888125466000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555e2dba28 CR3: 000000006a30a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:57 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x5c3/0x10c0 arch/x86/mm/tlb.c:1472
 flush_tlb_page arch/x86/include/asm/tlbflush.h:323 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
 wp_page_copy mm/memory.c:3846 [inline]
 do_wp_page+0x4129/0x5a00 mm/memory.c:4241
 handle_pte_fault mm/memory.c:6332 [inline]
 __handle_mm_fault mm/memory.c:6454 [inline]
 handle_mm_fault+0x1520/0x3310 mm/memory.c:6623
 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f0b87761220
Code: ac 28 00 48 8d 0c 1e 49 39 d0 49 89 48 60 0f 95 c2 48 29 d8 0f b6 d2 48 83 c8 01 48 c1 e2 02 48 09 da 48 83 ca 01 48 89 56 08 <48> 89 41 08 48 8d 4e 10 eb b0 48 8d 0d 5f df 0c 00 ba 9e 10 00 00
RSP: 002b:00007fff4f23dc50 EFLAGS: 00010206
RAX: 00000000000065e1 RBX: 0000000000008040 RCX: 000055555e2dba20
RDX: 0000000000008041 RSI: 000055555e2d39e0 RDI: 0000000000000004
RBP: 0000000000000802 R08: 00007f0b879ebe20 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000008030
R13: 0000000000000000 R14: 00007f0b879ebe80 R15: 0000000000000000
 </TASK>