rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1205/1:b..l P9895/1:b..l rcu: (detected by 1, t=10502 jiffies, g=35837, q=1533935 ncpus=2) task:syz.4.1089 state:R running task stack:27528 pid:9895 tgid:9893 ppid:5815 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x60e0 kernel/sched/core.c:6907 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7234 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__read_once_word_nocheck+0x3/0x10 include/asm-generic/rwonce.h:68 Code: 64 8e e8 e0 96 7f ff e9 c7 f9 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 07 cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc9000381f168 EFLAGS: 00000202 RAX: ffffffff8957cfa5 RBX: 0000000000000001 RCX: ffffffff9207f282 RDX: ffffc9000381f601 RSI: ffffc9000381f608 RDI: ffffc9000381f608 RBP: ffffc9000381f228 R08: ffffffff9207f286 R09: 0000000000000007 R10: 0000000000000200 R11: 00000000000856c9 R12: ffffc9000381f230 R13: ffffc9000381f1e0 R14: ffffc9000381f610 R15: ffffc9000381f214 deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline] unwind_next_frame+0xb1d/0x1ea0 arch/x86/kernel/unwind_orc.c:600 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1432 [inline] __free_frozen_pages+0x7ca/0x10a0 mm/page_alloc.c:2977 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5177 [inline] __kmalloc_node_track_caller_noprof+0x304/0x850 mm/slub.c:5285 kmalloc_reserve+0xe8/0x350 net/core/skbuff.c:635 __alloc_skb+0x185/0x710 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] nlmsg_new include/net/netlink.h:1055 [inline] ctrl_build_family_msg+0x36/0xa0 net/netlink/genetlink.c:1388 ctrl_getfamily+0x361/0x550 net/netlink/genetlink.c:1468 genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x4aa/0x520 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0677b5c84e RSP: 002b:00007f0678992e88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f06789946c0 RCX: 00007f0677b5c84e RDX: 0000000000000020 RSI: 00007f0678993000 RDI: 0000000000000004 RBP: 0000000000000000 R08: 00007f0678992f04 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 R13: 00007f0678992f58 R14: 00007f0678993000 R15: 0000000000000000 task:kworker/0:2 state:R running task stack:22280 pid:1205 tgid:1205 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x60e0 kernel/sched/core.c:6907 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7234 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x39/0x70 kernel/kcov.c:217 Code: 65 48 8b 15 41 47 04 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 c3 cc cc cc cc 8b 82 54 16 00 00 85 c0 74 f1 <8b> 82 30 16 00 00 83 f8 02 75 e6 48 8b 8a 38 16 00 00 8b 92 34 16 RSP: 0018:ffffc90004c7e860 EFLAGS: 00000246 RAX: 0000000080000000 RBX: ffff88801d934428 RCX: ffffffff8281cf7b RDX: ffff888029872480 RSI: ffffffff8281cf89 RDI: ffff888029872480 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88801d9343e0 R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000000 __page_table_check_zero+0x1a9/0x410 mm/page_table_check.c:143 page_table_check_free include/linux/page_table_check.h:46 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7ba/0x10a0 mm/page_alloc.c:2977 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:406 kmalloc_noprof include/linux/slab.h:962 [inline] usb_control_msg+0xbc/0x4a0 drivers/usb/core/message.c:144 usbhid_get_raw_report drivers/hid/usbhid/hid-core.c:891 [inline] usbhid_raw_request+0x418/0x600 drivers/hid/usbhid/hid-core.c:1312 __hid_hw_raw_request drivers/hid/hid-core.c:2493 [inline] hid_hw_raw_request+0x10b/0x150 drivers/hid/hid-core.c:2515 cp2112_hid_get.constprop.0+0x51/0x90 drivers/hid/hid-cp2112.c:327 cp2112_probe+0x238/0x2d0 drivers/hid/hid-cp2112.c:1253 __hid_device_probe drivers/hid/hid-core.c:2775 [inline] hid_device_probe+0x50e/0x800 drivers/hid/hid-core.c:2812 call_driver_probe drivers/base/dd.c:583 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:661 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833 __device_attach_driver+0x1ff/0x3e0 drivers/base/dd.c:961 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1033 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1088 bus_probe_device+0x64/0x160 drivers/base/bus.c:574 device_add+0x11d9/0x1950 drivers/base/core.c:3689 hid_add_device+0x2bf/0x440 drivers/hid/hid-core.c:2951 usbhid_probe+0xd57/0x1350 drivers/hid/usbhid/hid-core.c:1450 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:583 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:661 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833 __device_attach_driver+0x1ff/0x3e0 drivers/base/dd.c:961 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1033 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1088 bus_probe_device+0x64/0x160 drivers/base/bus.c:574 device_add+0x11d9/0x1950 drivers/base/core.c:3689 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2210 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291 call_driver_probe drivers/base/dd.c:583 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:661 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833 __device_attach_driver+0x1ff/0x3e0 drivers/base/dd.c:961 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1033 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1088 bus_probe_device+0x64/0x160 drivers/base/bus.c:574 device_add+0x11d9/0x1950 drivers/base/core.c:3689 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695 hub_port_connect drivers/usb/core/hub.c:5567 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x314d/0x4af0 drivers/usb/core/hub.c:5953 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 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 8633 jiffies! g35837 f0x2 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:28680 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x60e0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7004 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 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: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 98 83 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 43 2c 1d 00 fb f4 bc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197df0 EFLAGS: 00000242 RAX: 0000000002640767 RBX: ffff88801e6aa480 RCX: ffffffff8b8e5c75 RDX: 0000000000000000 RSI: ffffffff8de6cf89 RDI: ffffffff8c1adf20 RBP: 0000000000000001 R08: 0000000000000001 R09: ffffed10170a6795 R10: ffff8880b8533cab R11: 0000000000000000 R12: ffffed1003cd5490 R13: 0000000000000001 R14: ffffffff90d92f10 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124452000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555559b234e8 CR3: 0000000077290000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:73 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x35b/0x4b0 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148