rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=69f/1/0x4000000000000002 softirq=86552/86553 fqs=3 
	(detected by 1, t=10505 jiffies, g=124285, q=74)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 30713 Comm: syz.4.6449 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:kasan_check_range+0x0/0x290 mm/kasan/generic.c:188
Code: 48 01 c6 48 89 c7 e8 df 46 04 08 31 c0 c3 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 00 00 cc cc 00 00 cc cc 00 00 cc cc <b0> 01 48 85 f6 0f 84 ac 01 00 00 55 41 57 41 56 41 54 53 49 89 f8
RSP: 0018:ffffc90000006bd8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000015 RCX: ffffffff815d067f
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff910150c0
RBP: ffffc90000006e28 R08: dffffc0000000000 R09: 1ffffffff2202a18
R10: dffffc0000000000 R11: fffffbfff2202a19 R12: 000000009385b885
R13: ffff888024859dc0 R14: 00000000c8f91187 R15: ffff88802485a9c0
FS:  00007f426ad666c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff6bb8e7c62 CR3: 000000006076d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000200000000440 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 hlock_class kernel/locking/lockdep.c:197 [inline]
 __lock_acquire+0x12df/0x7d40 kernel/locking/lockdep.c:5117
 lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 __perf_output_begin kernel/events/ring_buffer.c:163 [inline]
 perf_output_begin_forward+0xa5/0xa30 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7814 [inline]
 perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_swevent_overflow kernel/events/core.c:9601 [inline]
 perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639
 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 82 fc 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007760 EFLAGS: 00000206
RAX: fcaaa7310496ef00 RBX: 1ffff92000000ef0 RCX: fcaaa7310496ef00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4c00
RBP: ffffc90000007840 R08: ffffffff9101518f R09: 1ffffffff2202a31
R10: dffffc0000000000 R11: fffffbfff2202a32 R12: ffffffff8d123400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 __ip_queue_xmit+0x127d/0x1c60 net/ipv4/ip_output.c:539
 __tcp_transmit_skb+0x1ca3/0x31e0 net/ipv4/tcp_output.c:1404
 tcp_delack_timer_handler+0x2f8/0x700 net/ipv4/tcp_timer.c:314
 tcp_delack_timer+0x18d/0x2f0 net/ipv4/tcp_timer.c:341
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 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:sysfs_add_file_mode_ns+0xc1/0x390 fs/sysfs/file.c:272
Code: 48 89 e8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 ef e8 23 79 d0 ff 48 8b 6d 00 48 83 c5 08 48 89 e8 48 c1 e8 03 42 80 3c 20 00 <74> 08 48 89 ef e8 05 79 d0 ff 48 8b 6d 00 48 85 ed 0f 84 69 02 00
RSP: 0018:ffffc90003c6f920 EFLAGS: 00000246
RAX: 1ffffffff1b23d7d RBX: ffff888064feabc8 RCX: 0000000000080000
RDX: ffffc900110e4000 RSI: 000000000003c55a RDI: 000000000003c55b
RBP: ffffffff8d91ebe8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1a49f65 R12: dffffc0000000000
R13: ffff88804d59a608 R14: ffffffff8e258ee0 R15: ffffffff8be4d300
 create_files fs/sysfs/group.c:64 [inline]
 internal_create_group+0x492/0xd00 fs/sysfs/group.c:149
 internal_create_groups fs/sysfs/group.c:189 [inline]
 sysfs_create_groups+0x55/0x120 fs/sysfs/group.c:215
 device_add_groups drivers/base/core.c:2491 [inline]
 device_add_attrs+0x82/0x690 drivers/base/core.c:2639
 device_add+0x677/0x1050 drivers/base/core.c:3363
 netdev_register_kobject+0x184/0x320 net/core/net-sysfs.c:2014
 register_netdevice+0x10e8/0x1720 net/core/dev.c:10423
 ppp_unit_register drivers/net/ppp/ppp_generic.c:1232 [inline]
 ppp_dev_configure+0x81a/0xaa0 drivers/net/ppp/ppp_generic.c:1288
 ppp_create_interface drivers/net/ppp/ppp_generic.c:3365 [inline]
 ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:1073 [inline]
 ppp_ioctl+0x8c2/0x1a70 drivers/net/ppp/ppp_generic.c:743
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 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: 0033:0x7f426cb0e2d9
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:00007f426ad66028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f426cd95fa0 RCX: 00007f426cb0e2d9
RDX: 000000110e22fff6 RSI: 00000000c004743e RDI: 000000000000000d
RBP: 00007f426cba5888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f426cd96038 R14: 00007f426cd95fa0 R15: 00007ffca5a73be8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10495 jiffies! g124285 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=61549
rcu: rcu_preempt kthread starved for 10496 jiffies! g124285 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27408 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/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: 4174 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 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+0x1110/0x1270 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+0x845/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 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+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 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:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x159/0x1b0 arch/x86/kernel/kvm.c:918
Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4b 0f b6 1f e8 47 a5 4a 00 44 38 e3 75 10 66 90 0f 00 2d 89 d9 f3 08 fb f4 <e9> 16 ff ff ff fb e9 10 ff ff ff e8 b7 6c 8d 08 89 f9 80 e1 07 38
RSP: 0018:ffffc9000321f8a0 EFLAGS: 00000246
RAX: 72bc3bafe63ddc00 RBX: 0000000000000003 RCX: 72bc3bafe63ddc00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4c00
RBP: ffffc9000321f950 R08: ffffffff9101518f R09: 1ffffffff2202a31
R10: dffffc0000000000 R11: fffffbfff2202a32 R12: 0000000000000003
R13: dffffc0000000000 R14: dffffc0000000000 R15: 1ffff92000643f14
 pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x605/0x9b0 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115
 spin_lock_bh include/linux/spinlock.h:369 [inline]
 lock_sock_nested+0x68/0x100 net/core/sock.c:3261
 lock_sock include/net/sock.h:1744 [inline]
 tcp_sendmsg+0x1d/0x40 net/ipv4/tcp.c:1459
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 sock_write_iter+0x2a6/0x3a0 net/socket.c:1090
 call_write_iter include/linux/fs.h:2179 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x748/0xd70 fs/read_write.c:594
 ksys_write+0x153/0x260 fs/read_write.c:647
 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: 0033:0x7ff6bda30457
Code: 48 89 fa 4c 89 df e8 a8 56 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff94628160 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055558e896500 RCX: 00007ff6bda30457
RDX: 00000000000002b0 RSI: 00007ff6b74d6d50 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000002b0
R13: 000055558e8aafb0 R14: 00007fff94628700 R15: 00007ff6b74d6d50
 </TASK>