rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=42bc/1/0x4000000000000000 softirq=197687/197688 fqs=0
rcu: (detected by 1, t=10502 jiffies, g=182457, q=95 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 27813 Comm: kworker/u8:20 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:taprio_set_budgets+0x181/0x310 net/sched/sch_taprio.c:675
Code: 20 49 83 fc 0f 0f 87 6e 01 00 00 4c 89 e8 48 c1 e8 03 42 80 3c 38 00 0f 85 4f 01 00 00 49 69 45 00 e8 03 00 00 31 d2 49 f7 f6 <49> 89 c6 e8 f7 f6 3e f8 49 83 fc 10 0f 87 e3 00 00 00 be 04 00 00
RSP: 0018:ffffc90000007d20 EFLAGS: 00000046
RAX: 00000000000000c0 RBX: ffff888058908884 RCX: ffffffff897fecba
RDX: 00000000000000c8 RSI: 0000000000000008 RDI: ffff8880326952a0
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffed10064d2a54
R10: ffff8880326952a7 R11: ffff88804d402ff0 R12: 0000000000000001
R13: ffff888058908808 R14: 0000000000000190 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8881248f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000057eff8 CR3: 00000000500bb000 CR4: 00000000003526f0
Call Trace:
advance_sched+0x5f6/0xc80 net/sched/sch_taprio.c:983
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:___slab_alloc+0x6b4/0x1c90 mm/slub.c:4735
Code: 85 d2 74 0a 80 7b 30 01 74 04 90 0f 0b 90 c6 43 30 00 41 f7 c6 00 02 00 00 0f 85 9b 03 00 00 9c 58 f6 c4 02 0f 85 83 05 00 00 <48> 8b 45 c8 65 48 2b 05 e8 d2 95 11 0f 85 df 12 00 00 48 8d 65 d0
RSP: 0018:ffffc9000beb78a0 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff8880b843f510 RCX: ffff888079b9a000
RDX: 0000000000000000 RSI: ffffffff8dacdb2d RDI: ffffffff8bf2b300
RBP: ffffc9000beb7940 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9088aed7 R11: ffff88804d402ff0 R12: 0000000000000000
R13: ffff88813ff27140 R14: 0000000000000286 R15: 0000000000000000
__slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4779
__slab_alloc_node mm/slub.c:4855 [inline]
slab_alloc_node mm/slub.c:5251 [inline]
__do_kmalloc_node mm/slub.c:5656 [inline]
__kmalloc_node_track_caller_noprof+0x4d6/0x930 mm/slub.c:5764
kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:608
__alloc_skb+0x186/0x410 net/core/skbuff.c:690
alloc_skb include/linux/skbuff.h:1383 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline]
nsim_dev_trap_report_work+0x2b1/0xcf0 drivers/net/netdevsim/dev.c:921
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: rcu_preempt kthread starved for 10502 jiffies! g182457 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:28064 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 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: 3488 Comm: kworker/u8:12 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xdfd/0x15e0 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 b5 5a 0c 00 f3 90 <41> 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 b6 05 00 00 8b 43 08 31
RSP: 0018:ffffc9000c4d7808 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b84431e0 RCX: ffffffff81b28971
RDX: ffff888032dda4c0 RSI: ffffffff81b2894b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: ffff888032ddaff0 R12: dffffc0000000000
R13: ffffed101708863d R14: 0000000000000001 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881249f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000057f000 CR3: 000000000e184000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2711 [inline]
smp_text_poke_batch_finish+0x5ad/0xdb0 arch/x86/kernel/alternative.c:2983
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_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate mm/kfence/core.c:874 [inline]
toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:866
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246