rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (2 ticks this GP) idle=43a4/1/0x4000000000000000 softirq=17987/17987 fqs=0
rcu: (detected by 0, t=10505 jiffies, g=10561, q=908 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6064 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x20/0x70 kernel/kcov.c:217
Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 d0 a0 92 65 8b 15 88 22 e1 10 81 e2 00 01 ff 00 74 11 <81> fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 74 2c 8b 91 18 16 00
RSP: 0018:ffffc90000a08d38 EFLAGS: 00000006
RAX: ffffffff81adb4c7 RBX: ffff8880b8727bc8 RCX: ffff8880306c3c00
RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000007
RBP: ffffc90000a08e90 R08: ffff888143bfc15f R09: 1ffff1102877f82b
R10: dffffc0000000000 R11: ffffed102877f82c R12: ffff888143bfc340
R13: 0000000000000001 R14: 0000000000000001 R15: ffff8880306c46d8
FS: 00007f32068f96c0(0000) GS:ffff888125d13000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055bd42748660 CR3: 0000000029982000 CR4: 00000000003526f0
Call Trace:
cpu_max_bits_warn include/linux/cpumask.h:135 [inline]
cpumask_check include/linux/cpumask.h:142 [inline]
cpumask_test_cpu include/linux/cpumask.h:646 [inline]
cpu_online include/linux/cpumask.h:1205 [inline]
trace_hrtimer_expire_exit include/trace/events/timer.h:306 [inline]
__run_hrtimer kernel/time/hrtimer.c:1764 [inline]
__hrtimer_run_queues+0x577/0xc60 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 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+0x2c5/0x310 kernel/locking/lockdep.c:6616
Code: 65 48 8b 05 4d 4d 03 11 48 3b 44 24 10 0f 84 26 fe ff ff e8 0d 84 dd 09 e8 38 85 dd 09 41 f7 c7 00 02 00 00 74 bd fb 40 84 ed <75> bc eb cd 90 0f 0b 90 e9 19 ff ff ff 90 0f 0b 90 e9 2a ff ff ff
RSP: 0018:ffffc900033d7088 EFLAGS: 00000246
RAX: 9659ce0313e86a00 RBX: ffff888030130a98 RCX: 9659ce0313e86a00
RDX: ffffffff93649338 RSI: ffffffff8d9ce014 RDI: ffffffff8be33f00
RBP: ffff888030130a00 R08: 0000000000000000 R09: ffffffff81aa8548
R10: dffffc0000000000 R11: fffffbfff1f47207 R12: 0000000000000000
R13: 0000000000001000 R14: 0000000000000000 R15: 0000000000000202
__qdisc_destroy+0x166/0x420 net/sched/sch_generic.c:1083
taprio_attach+0x25a/0x380 net/sched/sch_taprio.c:2160
qdisc_graft+0x1175/0x1590 net/sched/sch_api.c:1162
__tc_modify_qdisc net/sched/sch_api.c:1756 [inline]
tc_modify_qdisc+0x189b/0x20e0 net/sched/sch_api.c:1812
rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6963
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:729
____sys_sendmsg+0x505/0x830 net/socket.c:2614
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
__sys_sendmsg net/socket.c:2700 [inline]
__do_sys_sendmsg net/socket.c:2705 [inline]
__se_sys_sendmsg net/socket.c:2703 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f320598eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f32068f9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3205be5fa0 RCX: 00007f320598eec9
RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 0000000000000004
RBP: 00007f3205a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3205be6038 R14: 00007f3205be5fa0 R15: 00007ffc948e6448
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g10561 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=5893
rcu: rcu_preempt kthread starved for 10505 jiffies! g10561 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27160 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
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+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245