rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: (detected by 1, t=10502 jiffies, g=183477, q=313 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295156261-4295145759), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g183477 f0x2 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:27672 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x116a/0x5dd0 kernel/sched/core.c:6786
__schedule_loop kernel/sched/core.c:6864 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6879
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054
rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16110 Comm: kworker/0:4 Not tainted 6.16.0-syzkaller-00857-gced1b9e0392d #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: usb_hub_wq hub_event
RIP: 0010:rb_erase_cached include/linux/rbtree.h:123 [inline]
RIP: 0010:timerqueue_del+0x67/0x150 lib/timerqueue.c:57
Code: b6 32 f6 49 39 dc 0f 84 af 00 00 00 e8 a2 bb 32 f6 4c 8d 65 08 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 80 3c 02 00 <0f> 85 a3 00 00 00 48 39 5d 08 74 58 e8 78 bb 32 f6 48 89 ee 48 89
RSP: 0018:ffffc900000076b8 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff88823bede340 RCX: ffffffff8b893d70
RDX: 1ffff11017084fbb RSI: ffffffff8b893d7e RDI: 0000000000000006
RBP: ffff8880b8427dd0 R08: 0000000000000006 R09: 0000000000000001
R10: ffff88823bede340 R11: 0000000000000001 R12: ffff8880b8427dd8
R13: 0000000000000000 R14: ffff8880b8427c80 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881246f9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000057eff8 CR3: 00000000332da000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 00000000fec0007f DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
__remove_hrtimer+0x99/0x290 kernel/time/hrtimer.c:1121
__run_hrtimer kernel/time/hrtimer.c:1741 [inline]
__hrtimer_run_queues+0x4f9/0xad0 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__orc_find+0x49/0xf0 arch/x86/kernel/unwind_orc.c:100
Code: 00 49 89 fe 48 89 f0 49 39 fc 72 7b 48 b9 00 00 00 00 00 fc ff df 49 89 ff 48 89 fd eb 0c 48 8d 6b 04 49 89 df 49 39 ec 72 4e <4c> 89 e2 48 29 ea 48 89 d6 48 c1 ea 3f 48 c1 fe 02 48 01 f2 48 d1
RSP: 0018:ffffc90000007998 EFLAGS: 00000246
RAX: ffffffff91407a7a RBX: 0000000000000001 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: ffffffff91407a7a RDI: ffffffff90bba56c
RBP: ffffffff90bba56c R08: ffffffff91407a80 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000008609 R12: ffffffff90bba56c
R13: ffffffff81860994 R14: ffffffff90bba56c R15: ffffffff90bba56c
orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
unwind_next_frame+0x2ec/0x20a0 arch/x86/kernel/unwind_orc.c:494
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2381 [inline]
slab_free_after_rcu_debug+0x10d/0x340 mm/slub.c:4693
rcu_do_batch kernel/rcu/tree.c:2576 [inline]
rcu_core+0x79c/0x14e0 kernel/rcu/tree.c:2832
handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__rcu_read_unlock+0x11d/0x580 kernel/rcu/tree_plugin.h:445
Code: 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 75 01 00 00 8b 83 44 04 00 00 3d ff ff ff 3f 0f 87 49 01 00 00 5b 5d 41 5c <41> 5d 41 5e e9 5a b9 ed 09 65 8b 1d 23 26 30 12 f7 c3 00 00 f0 00
RSP: 0018:ffffc90004b177c0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffc90004b1779c
RDX: 0000000000000000 RSI: ffffffff8de10c2d RDI: ffff8880327ca884
RBP: ffff88801c6f4800 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: ffff88803a206780 R14: dffffc0000000000 R15: 0000000000000000
rcu_read_unlock include/linux/rcupdate.h:873 [inline]
class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
kernfs_root+0xf8/0x2a0 fs/kernfs/kernfs-internal.h:75
kernfs_next_descendant_post+0x1bb/0x420 fs/kernfs/dir.c:1373
__kernfs_remove+0x118/0x8a0 fs/kernfs/dir.c:1490
kernfs_remove_by_name_ns+0x68/0x110 fs/kernfs/dir.c:1717
kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
sysfs_unmerge_group+0xe7/0x170 fs/sysfs/group.c:402
rpm_sysfs_remove drivers/base/power/sysfs.c:823 [inline]
dpm_sysfs_remove+0x7f/0xb0 drivers/base/power/sysfs.c:832
device_del+0x1a0/0x9f0 drivers/base/core.c:3856
usb_disconnect+0x5bf/0x9c0 drivers/usb/core/hub.c:2375
hub_port_connect drivers/usb/core/hub.c:5406 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
port_event drivers/usb/core/hub.c:5870 [inline]
hub_event+0x1c81/0x4fe0 drivers/usb/core/hub.c:5952
process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3321 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245