rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10500 ticks this GP) idle=6a9c/1/0x4000000000000000 softirq=18462/18469 fqs=0 rcu: (t=10501 jiffies g=10121 q=119 ncpus=2) rcu: rcu_preempt kthread timer wakeup didn't happen for 10500 jiffies! g10121 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=3172 rcu: rcu_preempt kthread starved for 10501 jiffies! g10121 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6104 Comm: syz-executor.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__lock_acquire+0xb7e/0x1ce0 kernel/locking/lockdep.c:5223 Code: 84 6a 05 00 00 90 31 c0 e9 a4 fb ff ff c7 44 24 18 ff ff ff ff b9 fe ff ff ff c7 44 24 28 ff ff ff ff c7 44 24 20 ff ff ff ff 44 24 34 01 00 00 00 e9 f7 f9 ff ff 4c 89 e7 48 89 14 24 e8 29 RSP: 0018:ffffc90000007c38 EFLAGS: 00000002 RAX: 0000000000000048 RBX: ffff888031992f30 RCX: 00000000fffffffe RDX: 0000000000000000 RSI: ffff888031992f58 RDI: ffff888031992440 RBP: 0000000000000000 R08: 0000000000080000 R09: 0000000000000001 R10: 0000000000000028 R11: 0000000000000001 R12: ffff888031992f58 R13: ffff888031992440 R14: 0000000000000001 R15: 0000000000000003 FS: 00007f50c579b6c0(0000) GS:ffff8881246b4000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50c577ad58 CR3: 000000007be3c000 CR4: 00000000003526f0 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] advance_sched+0xd9/0xc80 net/sched/sch_taprio.c:929 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 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+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lockdep_unregister_key+0xe9/0x140 kernel/locking/lockdep.c:6616 Code: 48 89 ef e8 b9 e5 ff ff 48 83 2d 89 11 5f 14 01 89 c3 e8 da ee ff ff 9c 58 f6 c4 02 75 52 41 f7 c4 00 02 00 00 74 01 fb 84 db <75> 1b 5b 5d 41 5c e9 4c 76 0a 00 8b 05 4a 2b 14 0f 31 db 85 c0 74 RSP: 0018:ffffc900049cf318 EFLAGS: 00000246 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8df45eff RDI: ffffffff8c163300 RBP: ffffffff975b8a38 R08: 000000000000b168 R09: ffffffff95f7ecb0 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000246 R13: ffff8880237fc000 R14: ffff88807ce88000 R15: ffff8880237fc000 __qdisc_destroy+0x11a/0x4d0 net/sched/sch_generic.c:1083 qdisc_put+0xab/0xe0 net/sched/sch_generic.c:1109 taprio_attach+0x1fc/0x370 net/sched/sch_taprio.c:2160 qdisc_graft+0xe3c/0x17c0 net/sched/sch_api.c:1162 __tc_modify_qdisc net/sched/sch_api.c:1756 [inline] tc_modify_qdisc+0xf5c/0x2170 net/sched/sch_api.c:1812 rtnetlink_rcv_msg+0x3c6/0xe90 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5a7/0x870 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg net/socket.c:729 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2614 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2668 __sys_sendmsg+0x16d/0x220 net/socket.c:2700 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f50c4a7cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f50c579b0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f50c4b9bf80 RCX: 00007f50c4a7cae9 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004 RBP: 00007f50c4ac847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f50c4b9bf80 R15: 00007ffc30feeb98 CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xdfd/0x1600 kernel/smp.c:877 Code: 57 48 8b 54 24 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 d5 ff 0b 00 f3 90 <41> 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31 RSP: 0018:ffffc90000127888 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8442000 RCX: ffffffff81af9d91 RDX: ffff88801e2d0000 RSI: ffffffff81af9d6b RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffed1017088401 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881247b4000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa0b28ae008 CR3: 000000000e380000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1044 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_disable_cpuslocked+0x158/0x1c0 kernel/jump_label.c:240 static_key_disable+0x1a/0x20 kernel/jump_label.c:248 toggle_allocation_gate mm/kfence/core.c:855 [inline] toggle_allocation_gate+0x145/0x280 mm/kfence/core.c:842 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245