rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5789/1:b..l P17609/3:b..l rcu: (detected by 1, t=10502 jiffies, g=101061, q=582 ncpus=2) task:syz.4.3085 state:R running task stack:24800 pid:17609 tgid:17606 ppid:16792 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7189 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xff/0x120 kernel/softirq.c:457 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:912 [inline] __dev_queue_xmit+0xa04/0x4950 net/core/dev.c:4905 dev_queue_xmit include/linux/netdevice.h:3418 [inline] __netlink_deliver_tap_skb net/netlink/af_netlink.c:307 [inline] __netlink_deliver_tap net/netlink/af_netlink.c:325 [inline] netlink_deliver_tap+0xa4d/0xcc0 net/netlink/af_netlink.c:338 __netlink_sendskb net/netlink/af_netlink.c:1260 [inline] netlink_broadcast_deliver net/netlink/af_netlink.c:1399 [inline] do_one_broadcast net/netlink/af_netlink.c:1488 [inline] netlink_broadcast_filtered+0x917/0xe90 net/netlink/af_netlink.c:1533 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] xfrm_nlmsg_multicast net/xfrm/xfrm_user.c:1602 [inline] xfrm_send_acquire+0x88d/0xcc0 net/xfrm/xfrm_user.c:3867 km_query+0xb4/0x260 net/xfrm/xfrm_state.c:2782 xfrm_state_find+0x3f41/0x91c0 net/xfrm/xfrm_state.c:1559 xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:2522 [inline] xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:2573 [inline] xfrm_resolve_and_create_bundle+0x49e/0x3500 net/xfrm/xfrm_policy.c:2871 xfrm_lookup_with_ifid+0x29b/0x1ce0 net/xfrm/xfrm_policy.c:3205 xfrm_lookup net/xfrm/xfrm_policy.c:3336 [inline] xfrm_lookup_route+0x3b/0x200 net/xfrm/xfrm_policy.c:3347 ip_route_output_flow+0x11e/0x150 net/ipv4/route.c:2939 udp_sendmsg+0x198a/0x2720 net/ipv4/udp.c:1409 inet_sendmsg+0x105/0x140 net/ipv4/af_inet.c:866 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x98d/0xb70 net/socket.c:2698 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752 __sys_sendmmsg+0x205/0x430 net/socket.c:2841 __do_sys_sendmmsg net/socket.c:2868 [inline] __se_sys_sendmmsg net/socket.c:2865 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2865 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f432ef9cdd9 RSP: 002b:00007f432ff43028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f432f215fa0 RCX: 00007f432ef9cdd9 RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000007 RBP: 00007f432f032d69 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000001c R11: 0000000000000246 R12: 0000000000000000 R13: 00007f432f216038 R14: 00007f432f215fa0 R15: 00007ffda4a3f0e8 task:kworker/0:7 state:R running task stack:23016 pid:5789 tgid:5789 ppid:2 task_flags:0x4288160 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7189 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__kasan_check_byte+0x4/0x50 mm/kasan/common.c:572 Code: 74 15 00 5d ba fe 00 00 00 41 5c 41 5d e9 04 2b 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 <41> 54 49 89 f4 55 48 89 fd 53 e8 9d 1e 00 00 89 c3 84 c0 74 0b 89 RSP: 0018:ffffc90005027618 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff82b917f4 RDI: ffffffff8e7e54e0 RBP: ffffffff8e7e54e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire kernel/locking/lockdep.c:5842 [inline] lock_acquire+0x12a/0x370 kernel/locking/lockdep.c:5825 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] kernfs_root+0x34/0x2a0 fs/kernfs/kernfs-internal.h:74 __kernfs_remove+0x83c/0xb80 fs/kernfs/dir.c:1546 kernfs_remove_by_name_ns+0x7c/0x120 fs/kernfs/dir.c:1798 kernfs_remove_by_name include/linux/kernfs.h:639 [inline] remove_files+0x96/0x1c0 fs/sysfs/group.c:28 sysfs_remove_group+0x8b/0x1b0 fs/sysfs/group.c:328 sysfs_remove_groups fs/sysfs/group.c:352 [inline] sysfs_remove_groups+0x60/0xb0 fs/sysfs/group.c:344 device_remove_groups drivers/base/core.c:2844 [inline] device_remove_attrs+0x192/0x290 drivers/base/core.c:2974 device_del+0x36e/0x9b0 drivers/base/core.c:3894 device_unregister+0x1d/0xe0 drivers/base/core.c:3936 usb_remove_ep_devs+0x42/0x90 drivers/usb/core/endpoint.c:181 usb_disconnect+0x561/0x9a0 drivers/usb/core/hub.c:2366 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+0x1d0c/0x4af0 drivers/usb/core/hub.c:5953 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 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 10500 jiffies! g101061 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:28904 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 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: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: 1 UID: 0 PID: 17597 Comm: syz.3.3083 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 79 7c 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 RSP: 0018:ffffc90004fe7b40 EFLAGS: 00000246 RAX: 0000000000080000 RBX: 0000000000000000 RCX: ffffc9001c8ab000 RDX: 0000000000080000 RSI: ffffffff81fc0f67 RDI: ffff888036cd4a00 RBP: ffff8880b8443320 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed1017088665 R14: 0000000000000001 R15: ffff8880b853c5c0 FS: 00007f5f1b1f06c0(0000) GS:ffff888124476000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33306ffc CR3: 000000003676a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: clock_was_set+0x62b/0x870 kernel/time/hrtimer.c:999 do_settimeofday64+0x330/0x4d0 kernel/time/timekeeping.c:1603 do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195 __do_sys_clock_settime kernel/time/posix-timers.c:1124 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1108 [inline] __x64_sys_clock_settime+0x1c1/0x2a0 kernel/time/posix-timers.c:1108 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5f1a39cdd9 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:00007f5f1b1f0028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007f5f1a615fa0 RCX: 00007f5f1a39cdd9 RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000 RBP: 00007f5f1a432d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5f1a616038 R14: 00007f5f1a615fa0 R15: 00007ffc361b9198