rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=1ba4/1/0x4000000000000000 softirq=15322/15323 fqs=0 rcu: (detected by 1, t=10505 jiffies, g=12225, q=119 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6075 Comm: syz-executor.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:qdisc_dev include/net/sch_generic.h:594 [inline] RIP: 0010:advance_sched+0x80/0xc90 net/sched/sch_taprio.c:922 Code: 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 38 e3 b5 f8 48 8b 1b 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <74> 08 48 89 df e8 16 e3 b5 f8 48 8b 1b 48 83 c3 36 48 89 d8 48 c1 RSP: 0018:ffffc90000007c70 EFLAGS: 00000046 RAX: 1ffff1100fb24000 RBX: ffff88807d920000 RCX: dffffc0000000000 RDX: 0000000000010000 RSI: 0000000000000000 RDI: ffff888025196300 RBP: ffffc90000007e90 R08: ffffffff8f822077 R09: 1ffffffff1f0440e R10: dffffc0000000000 R11: ffffffff89722ac0 R12: ffff888025196300 R13: ffff888025196000 R14: dffffc0000000000 R15: ffff88807c086698 FS: 00007fa4f61fe6c0(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa4f61ddd58 CR3: 000000007739b000 CR4: 0000000000350ef0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:debug_lockdep_rcu_enabled+0xd/0x40 kernel/rcu/update.c:320 Code: 8d 67 48 0f b9 3a 90 eb ca cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d 17 59 26 04 00 <74> 1e 83 3d 2a 88 26 04 00 74 15 65 48 8b 0c 25 08 b0 7e 92 31 c0 RSP: 0018:ffffc90004a4edb0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffffffff909e5801 RCX: ffffc90004a4f1c8 RDX: ffffc90004a4ee01 RSI: dffffc0000000000 RDI: ffffc90004a4ee90 RBP: dffffc0000000000 R08: ffffc90004a4f1b0 R09: ffffc90004a4eed8 R10: dffffc0000000000 R11: fffff52000949ddd R12: ffffc90004a4f1c0 R13: ffffc90004a48000 R14: ffffc90004a4ee88 R15: ffffffff81743f85 rcu_read_unlock include/linux/rcupdate.h:895 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x1a64/0x23d0 arch/x86/kernel/unwind_orc.c:695 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 ref_tracker_free+0xef/0x7d0 lib/ref_tracker.c:307 netdev_tracker_free include/linux/netdevice.h:4420 [inline] netdev_put include/linux/netdevice.h:4437 [inline] __qdisc_destroy+0x1ba/0x400 net/sched/sch_generic.c:1081 taprio_attach+0x25a/0x380 net/sched/sch_taprio.c:2161 qdisc_graft+0x1175/0x1590 net/sched/sch_api.c:1162 __tc_modify_qdisc net/sched/sch_api.c:1761 [inline] tc_modify_qdisc+0x16d3/0x2020 net/sched/sch_api.c:1817 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6967 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x820 net/socket.c:2592 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa4f6e7cae9 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:00007fa4f61fe0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fa4f6f9bf80 RCX: 00007fa4f6e7cae9 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004 RBP: 00007fa4f6ec847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fa4f6f9bf80 R15: 00007ffff3016828 rcu: rcu_preempt kthread starved for 10505 jiffies! g12225 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:27136 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 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+0x599/0xb30 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: 6077 Comm: syz-executor.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xcd4/0x12b0 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 4a 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 f5 95 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 d9 95 0b 00 eb e4 44 RSP: 0018:ffffc90004a5f940 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110170c856d RCX: ffff88807c080000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90004a5fab0 R08: ffffffff8f822077 R09: 1ffffffff1f0440e R10: dffffc0000000000 R11: ffffffff8171a740 R12: ffff8880b8642b68 R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000 FS: 00007fa4f61dd6c0(0000) GS:ffff888125f35000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffddd68f088 CR3: 000000007739b000 CR4: 0000000000350ef0 Call Trace: clock_was_set+0x709/0x7c0 kernel/time/hrtimer.c:969 do_adjtimex+0x228/0x310 kernel/time/timekeeping.c:2767 do_clock_adjtime kernel/time/posix-timers.c:1161 [inline] __do_sys_clock_adjtime kernel/time/posix-timers.c:1173 [inline] __se_sys_clock_adjtime kernel/time/posix-timers.c:1164 [inline] __x64_sys_clock_adjtime+0x211/0x2c0 kernel/time/posix-timers.c:1164 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa4f6e7cae9 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:00007fa4f61dd0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007fa4f6f9c050 RCX: 00007fa4f6e7cae9 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000000 RBP: 00007fa4f6ec847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fa4f6f9c050 R15: 00007ffff3016828