rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=1eec/1/0x4000000000000000 softirq=32560/32561 fqs=0
rcu: (detected by 0, t=10506 jiffies, g=36905, q=302 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:2013 [inline]
RIP: 0010:__hrtimer_run_queues+0x362/0x9c0 kernel/time/hrtimer.c:2096
Code: 00 41 83 46 10 01 41 83 46 10 01 31 c9 31 d2 4c 89 e7 4c 89 f6 e8 9e df ff ff 49 8d 7c 24 48 48 89 f8 48 c1 e8 03 80 3c 18 00 <0f> 85 38 05 00 00 48 8b 74 24 30 48 8b 3c 24 4d 8b 6c 24 48 e8 65
RSP: 0018:ffffc90000a08e98 EFLAGS: 00000046
RAX: 1ffff11006b8d869 RBX: dffffc0000000000 RCX: ffffffff81f5f514
RDX: ffff88801f298000 RSI: ffffffff81f5f37b RDI: ffff888035c6c348
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888035c6c300
R13: 0000000000000001 R14: ffff8880b8528540 R15: ffff8880b8528590
FS: 0000000000000000(0000) GS:ffff888123eda000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2e0030 CR3: 0000000021373000 CR4: 00000000003526f0
Call Trace:
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 76 5f 27 f6 48 89 df e8 fe ae 27 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 05 be 16 f6 65 8b 05 4e c7 a5 08 85 c0 74 16 5b
RSP: 0018:ffffc900001e71f8 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffffffff90b4c220 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff8e1a76e9 RDI: ffffffff8c402680
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000246 R14: 0000000000000000 R15: 0000000000000000
spin_unlock_irqrestore include/linux/spinlock.h:408 [inline]
__wake_up_common_lock kernel/sched/wait.c:127 [inline]
__wake_up+0x3f/0x60 kernel/sched/wait.c:146
netlink_unlock_table net/netlink/af_netlink.c:462 [inline]
netlink_unlock_table net/netlink/af_netlink.c:459 [inline]
netlink_broadcast_filtered+0xa28/0xf20 net/netlink/af_netlink.c:1543
netlink_broadcast+0x39/0x50 net/netlink/af_netlink.c:1563
uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
kobject_uevent_env+0xcdd/0x18b0 lib/kobject_uevent.c:611
device_del+0x605/0x9b0 drivers/base/core.c:3979
device_unregister+0x1d/0xe0 drivers/base/core.c:4002
device_destroy+0x99/0xe0 drivers/base/core.c:4556
sound_remove_unit+0x149/0x200 sound/sound_core.c:306
snd_unregister_oss_device+0x194/0x2a0 sound/core/sound_oss.c:180
snd_rawmidi_dev_disconnect+0x456/0x690 sound/core/rawmidi.c:2071
__snd_device_disconnect sound/core/device.c:63 [inline]
__snd_device_disconnect sound/core/device.c:59 [inline]
snd_device_disconnect_all+0x111/0x1b0 sound/core/device.c:215
snd_card_disconnect.part.0+0x29e/0x5b0 sound/core/init.c:539
snd_card_disconnect+0x1f/0x30 sound/core/init.c:500
__usb_audio_disconnect sound/usb/card.c:1110 [inline]
usb_audio_disconnect+0x25c/0x680 sound/usb/card.c:1158
usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:618 [inline]
device_remove+0x12a/0x180 drivers/base/dd.c:610
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
device_del+0x376/0x9b0 drivers/base/core.c:3961
usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1478
usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2345
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x1c4f/0x4a60 drivers/usb/core/hub.c:5953
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
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
rcu: rcu_preempt kthread starved for 10506 jiffies! g36905 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:27432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
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
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 9290 Comm: syz.3.765 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x20 kernel/kcov.c:313
Code: 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 58 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 2a fe ff ff
RSP: 0018:ffffc900044cf628 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81fdc7c2
RDX: ffff888031b60000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880
FS: 0000000000000000(0000) GS:ffff888123dda000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33423ffc CR3: 00000000745af000 CR4: 00000000003526f0
Call Trace:
csd_lock_wait kernel/smp.c:342 [inline]
smp_call_function_many_cond+0x5b2/0x1870 kernel/smp.c:912
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1077
__flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:499 [inline]
tlb_flush_mmu mm/mmu_gather.c:423 [inline]
tlb_finish_mmu+0x3fe/0x810 mm/mmu_gather.c:549
exit_mmap+0x454/0xa00 mm/mmap.c:1313
__mmput+0x12a/0x410 kernel/fork.c:1187
mmput+0x67/0x80 kernel/fork.c:1210
exit_mm kernel/exit.c:615 [inline]
do_exit+0x8b1/0x2ae0 kernel/exit.c:997
do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff88a39e019
Code: Unable to access opcode bytes at 0x7ff88a39dfef.
RSP: 002b:00007ff88b1da0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007ff88a625fa8 RCX: 00007ff88a39e019
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff88a625fa8
RBP: 00007ff88a625fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff88a626038 R14: 00007ffc5d67faa0 R15: 00007ffc5d67fb88