rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14251/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=207577, q=738 ncpus=2)
task:kworker/0:11 state:R running task stack:20864 pid:14251 tgid:14251 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__rcu_read_unlock+0x0/0xe0 kernel/rcu/tree_plugin.h:431
Code: 89 d9 80 e1 07 80 c1 03 38 c1 7c dc 48 89 df e8 06 69 7f 00 eb d2 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000b5f7090 EFLAGS: 00000286
RAX: 3fc8aa0bcf787500 RBX: ffffffff9014d401 RCX: 0000000000000046
RDX: 0000000000000005 RSI: ffffffff8d97608a RDI: ffffffff8bc083e0
RBP: dffffc0000000000 R08: ffffc9000b5f7250 R09: ffffc9000b5f7218
R10: dffffc0000000000 R11: fffff520016bee45 R12: ffffc9000b5f7260
R13: ffffc9000b5f0000 R14: ffffc9000b5f71c8 R15: ffffffff8173fd65
rcu_read_unlock include/linux/rcupdate.h:899 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x1ab6/0x23d0 arch/x86/kernel/unwind_orc.c:695
__unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
discard_slab mm/slub.c:3346 [inline]
__put_partials+0x146/0x170 mm/slub.c:3886
__slab_free+0x294/0x320 mm/slub.c:5952
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_noprof+0x3cf/0x800 mm/slub.c:5669
kmalloc_noprof include/linux/slab.h:961 [inline]
usb_alloc_urb+0x46/0x150 drivers/usb/core/urb.c:75
usb_internal_control_msg drivers/usb/core/message.c:96 [inline]
usb_control_msg+0x118/0x3e0 drivers/usb/core/message.c:154
usb_clear_port_feature drivers/usb/core/hub.c:456 [inline]
port_event drivers/usb/core/hub.c:5765 [inline]
hub_event+0x82a/0x4ef0 drivers/usb/core/hub.c:5953
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: rcu_preempt kthread starved for 297 jiffies! g207577 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:27480 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 74 Comm: kworker/u8:5 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: bat_events batadv_tt_purge
RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:409 [inline]
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:419 [inline]
RIP: 0010:unwind_next_frame+0xd85/0x23d0 arch/x86/kernel/unwind_orc.c:600
Code: 00 0f 95 c0 49 39 df 0f 96 c1 20 c1 49 39 dc 0f 97 c0 20 c8 3c 01 75 18 48 8d 43 08 4c 39 f8 0f 97 c1 4c 39 e0 0f 96 c0 84 c1 <0f> 85 bf 00 00 00 49 8d 7e 28 48 89 f8 48 c1 e8 03 48 b9 00 00 00
RSP: 0018:ffffc90000a07e38 EFLAGS: 00000202
RAX: ffffc90000a08901 RBX: ffffc90000a08928 RCX: 1ffff92000140f01
RDX: ffffffff90a17762 RSI: 0000000000000002 RDI: ffffffff8bc08380
RBP: 1ffff92000140fe2 R08: 0000000000000003 R09: ffffffff8df41aa0
R10: dffffc0000000000 R11: ffffffff81acf3d0 R12: ffffc90000a09000
R13: 1ffff92000140fe3 R14: ffffc90000a07f08 R15: ffffc90000a01000
FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055559209f5c8 CR3: 0000000026ed6000 CR4: 0000000000350ef0
Call Trace:
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6670 [inline]
kmem_cache_free+0x197/0x620 mm/slub.c:6781
skb_release_data+0x62d/0x7c0 net/core/skbuff.c:1107
skb_release_all net/core/skbuff.c:1182 [inline]
__kfree_skb net/core/skbuff.c:1196 [inline]
consume_skb+0x9e/0xf0 net/core/skbuff.c:1428
nft_synproxy_eval_v6+0x376/0x560 net/netfilter/nft_synproxy.c:91
nft_synproxy_do_eval+0x3d7/0x570 net/netfilter/nft_synproxy.c:145
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500
NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6139 [inline]
__netif_receive_skb+0xd3/0x380 net/core/dev.c:6252
process_backlog+0x54f/0x1340 net/core/dev.c:6604
__napi_poll+0xae/0x320 net/core/dev.c:7668
napi_poll net/core/dev.c:7731 [inline]
net_rx_action+0x64a/0xe00 net/core/dev.c:7883
handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
spin_unlock_bh include/linux/spinlock.h:396 [inline]
batadv_tt_global_purge net/batman-adv/translation-table.c:2250 [inline]
batadv_tt_purge+0x4d1/0x9e0 net/batman-adv/translation-table.c:3510
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246