rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (4 ticks this GP) idle=5a5c/1/0x4000000000000000 softirq=94886/94886 fqs=6
rcu: (detected by 0, t=10502 jiffies, g=171193, q=288 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 22534 Comm: syz.3.5327 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:100 [inline]
RIP: 0010:do_raw_spin_unlock+0x61/0x230 kernel/locking/spinlock_debug.c:140
Code: 4e ad de 0f 85 ed 00 00 00 48 89 df be 04 00 00 00 e8 f3 01 76 00 48 89 d8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 6e 01 00 00 <83> 3b 00 0f 84 e4 00 00 00 4c 8d 73 10 4d 89 f5 49 c1 ed 03 43 80
RSP: 0018:ffffc900001f0c50 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88801ef412e8 RCX: ffffffff8169598d
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88801ef412e8
RBP: dffffc0000000000 R08: ffff88801ef412eb R09: 1ffff11003de825d
R10: dffffc0000000000 R11: ffffed1003de825e R12: dffffc0000000000
R13: ffff88801ef41000 R14: ffff88801ef412ec R15: ffff88801ef41340
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c4234b3 CR3: 000000000cf32000 CR4: 00000000003506e0
Call Trace:
__raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_unlock+0x1e/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
advance_sched+0x989/0xc70 net/sched/sch_taprio.c:998
__run_hrtimer kernel/time/hrtimer.c:1754 [inline]
__hrtimer_run_queues+0x525/0xc10 kernel/time/hrtimer.c:1818
hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900034c7300 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: c414adfc2e7f3600
RDX: 0000000000000000 RSI: ffffffff8acadce0 RDI: ffffffff8b1cf820
RBP: ffffc900034c7410 R08: dffffc0000000000 R09: 1ffffffff223cea0
R10: dffffc0000000000 R11: fffffbfff223cea1 R12: 1ffff92000698e6c
R13: ffffffff8d131da0 R14: 0000000000000246 R15: dffffc0000000000
rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
rcu_read_lock include/linux/rcupdate.h:786 [inline]
page_ext_get+0x3e/0x2b0 mm/page_ext.c:508
page_table_check_clear+0x4a/0x6a0 mm/page_table_check.c:74
ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
zap_pte_range mm/memory.c:1429 [inline]
zap_pmd_range mm/memory.c:1571 [inline]
zap_pud_range mm/memory.c:1600 [inline]
zap_p4d_range mm/memory.c:1621 [inline]
unmap_page_range+0x1c35/0x32f0 mm/memory.c:1642
unmap_vmas+0x286/0x3f0 mm/memory.c:1732
exit_mmap+0x238/0xb90 mm/mmap.c:3302
__mmput+0x118/0x3a0 kernel/fork.c:1357
exit_mm+0x23f/0x340 kernel/exit.c:570
do_exit+0x909/0x2530 kernel/exit.c:871
do_group_exit+0x22d/0x2f0 kernel/exit.c:1026
get_signal+0x12a6/0x1390 kernel/signal.c:2903
arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f88eeb9de59
Code: Unable to access opcode bytes at 0x7f88eeb9de2f.
RSP: 002b:00007f88ef9eb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: 000000000000000b RBX: 00007f88eee25fa0 RCX: 00007f88eeb9de59
RDX: 0000000000000318 RSI: 00002000000bd000 RDI: 0000000000000004
RBP: 00007f88eec33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f88eee26038 R14: 00007f88eee25fa0 R15: 00007ffffb60c5b8
rcu: rcu_preempt kthread starved for 10490 jiffies! g171193 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:26856 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x15ae/0x4660 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 10172 Comm: kworker/u4:31 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xd85/0x1190 kernel/smp.c:855
Code: 45 8b 34 24 44 89 f6 83 e6 01 31 ff e8 34 f1 0a 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 6f ed 0a 00 eb 38 f3 90 <42> 0f b6 04 33 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 53 ed
RSP: 0018:ffffc9000f9ef780 EFLAGS: 00000293
RAX: ffffffff817bf7fd RBX: 1ffff110171e82bd RCX: ffff88801d381e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000f9ef900 R08: ffffffff911e7507 R09: 1ffffffff223cea0
R10: dffffc0000000000 R11: fffffbfff223cea1 R12: ffff8880b8f415e8
R13: ffff8880b8e3d3c0 R14: dffffc0000000000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc8679b088 CR3: 000000000cf32000 CR4: 00000000003506f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022
on_each_cpu include/linux/smp.h:71 [inline]
text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
text_poke_bp_batch+0x31e/0x980 arch/x86/kernel/alternative.c:2432
text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
static_key_enable+0x1a/0x20 kernel/jump_label.c:220
toggle_allocation_gate+0xa8/0x260 mm/kfence/core.c:847
process_one_work kernel/workqueue.c:2653 [inline]
process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293