rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=b69c/1/0x4000000000000000 softirq=45061/45062 fqs=2 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11121/1:b..l rcu: (detected by 0, t=10502 jiffies, g=47097, q=273 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 11123 Comm: syz.4.1592 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:lock_release+0x7f/0x3c0 kernel/locking/lockdep.c:5881 Code: e6 46 b5 0e 00 0f 84 1c 02 00 00 65 8b 05 c9 f0 c9 11 85 c0 0f 85 0d 02 00 00 65 4c 8b 3d d1 ab c9 11 41 83 bf 9c 0b 00 00 00 <0f> 85 f7 01 00 00 49 81 3e 20 c5 2f 94 0f 84 ea 01 00 00 9c 5b fa RSP: 0018:ffffc90000a08d58 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000046 RCX: 0000000000010204 RDX: 0000000000010000 RSI: ffffffff8c4bd260 RDI: ffffffff8c4bd220 RBP: ffff8880236a6300 R08: ffff8880236a6327 R09: 0000000000000000 R10: ffff8880236a6318 R11: ffffed10046d4c65 R12: ffff8880b87281c0 R13: ffffffff81b30edf R14: ffff8880b87281d8 R15: ffff88801dfe3e00 FS: 00007f55afde66c0(0000) GS:ffff888125060000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000012c0 CR3: 0000000077f90000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_irqrestore+0x1b/0x80 kernel/locking/spinlock.c:198 __run_hrtimer kernel/time/hrtimer.c:2028 [inline] __hrtimer_run_queues+0x2bf/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 cd eb d1 f5 f7 c3 00 02 00 00 74 05 e8 90 d0 fd f5 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 d4 01 c3 f5 65 8b 05 ad 22 9b 07 85 c0 74 18 5b 41 5e e9 91 48 RSP: 0018:ffffc9000355eee8 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000282 RCX: 0000000080000202 RDX: 0000000000000002 RSI: ffffffff8e229452 RDI: 0000000000000001 RBP: ffffc9000355f1d0 R08: ffffffff905767f7 R09: 1ffffffff20aecfe R10: dffffc0000000000 R11: fffffbfff20aecff R12: ffff8880236a62a8 R13: dffffc0000000000 R14: ffff8880236a62a8 R15: ffff8880236a62f8 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] taprio_change+0x34f3/0x4640 net/sched/sch_taprio.c:1989 taprio_init+0x994/0xc00 net/sched/sch_taprio.c:2128 qdisc_create+0x7b5/0xf00 net/sched/sch_api.c:1323 __tc_modify_qdisc net/sched/sch_api.c:1757 [inline] tc_modify_qdisc+0x17af/0x2390 net/sched/sch_api.c:1821 rtnetlink_rcv_msg+0x7b9/0xc00 net/core/rtnetlink.c:7085 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f55aef9de59 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:00007f55afde6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f55af225fa0 RCX: 00007f55aef9de59 RDX: 0000000000000010 RSI: 00002000000012c0 RDI: 0000000000000005 RBP: 00007f55af033e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f55af226038 R14: 00007f55af225fa0 R15: 00007fffe5e875b8 task:syz.3.1591 state:R running task stack:25040 pid:11121 tgid:11120 ppid:5623 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xe1/0x130 kernel/softirq.c:457 local_bh_enable include/linux/bottom_half.h:33 [inline] bpf_test_run+0x3a8/0x830 net/bpf/test_run.c:425 bpf_prog_test_run_skb+0xe35/0x2230 net/bpf/test_run.c:1225 bpf_prog_test_run+0x2c5/0x340 kernel/bpf/syscall.c:4859 __sys_bpf+0xa22/0xd90 kernel/bpf/syscall.c:6436 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline] __se_sys_bpf kernel/bpf/syscall.c:6534 [inline] __x64_sys_bpf+0xba/0xd0 kernel/bpf/syscall.c:6534 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f846759de59 RSP: 002b:00007f84683e1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f8467825fa0 RCX: 00007f846759de59 RDX: 0000000000000050 RSI: 0000200000002300 RDI: 000000000000000a RBP: 00007f8467633e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8467826038 R14: 00007f8467825fa0 R15: 00007ffe08b0d1d8 rcu: rcu_preempt kthread starved for 10498 jiffies! g47097 f0x0 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:28192 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 0 UID: 0 PID: 5618 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x10b0/0x14b0 kernel/smp.c:892 Code: c0 75 73 41 8b 1e 89 de 83 e6 01 31 ff e8 d8 1e 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 84 1a 0c 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 69 1a 0c RSP: 0018:ffffc9000433f580 EFLAGS: 00000293 RAX: ffffffff81ba5757 RBX: dffffc0000000000 RCX: ffff88807abe9f00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000433f6a8 R08: ffffffff905767f7 R09: 1ffffffff20aecfe R10: dffffc0000000000 R11: fffffbfff20aecff R12: 1ffff110170e81d1 R13: ffff8880b863c448 R14: ffff8880b8740e88 R15: 0000000000000001 FS: 000055557f525500(0000) GS:ffff888124f60000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f84683c0d58 CR3: 000000005e8b8000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c4/0x1090 arch/x86/mm/tlb.c:1451 dup_mmap+0x1786/0x1d90 mm/mmap.c:1905 dup_mm kernel/fork.c:1538 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1590 copy_process+0x1e99/0x43f0 kernel/fork.c:2288 kernel_clone+0x2d7/0x940 kernel/fork.c:2747 __do_sys_clone kernel/fork.c:2888 [inline] __se_sys_clone kernel/fork.c:2872 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2872 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3e823c68d2 Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffe61694430 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe61694430 RCX: 00007f3e823c68d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe616945bc R08: 0000000000000000 R09: 0000000000000001 R10: 000055557f5257d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 0000000000048501 R15: 00007ffe61694610