rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=b304/1/0x4000000000000000 softirq=45002/45009 fqs=4
rcu: (detected by 1, t=10502 jiffies, g=37721, q=163 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10923 Comm: syz.4.1397 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline]
RIP: 0010:__raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
RIP: 0010:_raw_spin_lock_irq+0x68/0xf0 kernel/locking/spinlock.c:170
Code: 8b 49 89 e6 49 c1 ee 03 48 b8 f1 f1 f1 f1 00 f3 f3 f3 49 bf 00 00 00 00 00 fc ff df 4b 89 04 3e 48 c7 44 24 20 00 00 00 00 9c <8f> 44 24 20 8b 44 24 20 fa a9 00 02 00 00 74 05 e8 63 0f 40 f6 bf
RSP: 0018:ffffc90000007c98 EFLAGS: 00000802
RAX: f3f3f300f1f1f1f1 RBX: ffff8880b8627ac0 RCX: ffff88802ba6bc80
RDX: 0000000000010000 RSI: ffffffff8c03aa40 RDI: ffff8880b8627ac0
RBP: ffffc90000007d30 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce
R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff88807b3fa340
R13: dffffc0000000000 R14: 1ffff92000000f94 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8881259e7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33112ff8 CR3: 000000000e138000 CR4: 00000000003526f0
Call Trace:
__run_hrtimer kernel/time/hrtimer.c:1781 [inline]
__hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:stackdepot_memcmp lib/stackdepot.c:576 [inline]
RIP: 0010:find_stack lib/stackdepot.c:610 [inline]
RIP: 0010:stack_depot_save_flags+0x1be/0x860 lib/stackdepot.c:668
Code: 18 8b 74 24 04 85 db 75 5d 4d 8b 3f 4d 39 e7 74 52 41 39 6f 10 75 f2 45 39 57 14 75 ec 31 c0 49 8b 0c c6 49 3b 4c c7 20 75 df <48> ff c0 41 39 c5 75 ed 83 fe 02 72 2f 49 8d 7f 1c 41 8b 5f 1c 85
RSP: 0018:ffffc9001b357078 EFLAGS: 00000246
RAX: 000000000000000e RBX: ffff88802ba6c200 RCX: ffffffff8184637c
RDX: 000000006c6a7df5 RSI: 0000000000000001 RDI: 0000000088ae36da
RBP: 000000006d9d0ab0 R08: 00000000e669b673 R09: 000000001f3d371c
R10: 0000000000000010 R11: ffffffff81ac5170 R12: ffff88823bb0ab00
R13: 0000000000000010 R14: ffffc9001b357120 R15: ffff888055e24e80
save_stack+0x103/0x1f0 mm/page_owner.c:157
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906
__folio_put+0x21b/0x2c0 mm/swap.c:112
folio_put include/linux/mm.h:1440 [inline]
zpdesc_put mm/zpdesc.h:137 [inline]
__free_zspage+0x338/0x5b0 mm/zsmalloc.c:851
zs_free+0x395/0x510 mm/zsmalloc.c:1379
zswap_entry_free+0x345/0x500 mm/zswap.c:720
swap_range_free mm/swapfile.c:1276 [inline]
swap_entries_free+0x304/0x820 mm/swapfile.c:1712
swap_entries_put_map+0x63c/0x900 mm/swapfile.c:1634
swap_entries_put_map_nr mm/swapfile.c:1669 [inline]
free_swap_and_cache_nr+0x15d/0x3b0 mm/swapfile.c:1950
zap_nonpresent_ptes mm/memory.c:1748 [inline]
do_zap_pte_range mm/memory.c:1814 [inline]
zap_pte_range mm/memory.c:1854 [inline]
zap_pmd_range mm/memory.c:1946 [inline]
zap_pud_range mm/memory.c:1975 [inline]
zap_p4d_range mm/memory.c:1996 [inline]
unmap_page_range+0x1a64/0x4370 mm/memory.c:2017
unmap_single_vma mm/memory.c:2060 [inline]
unmap_vmas+0x399/0x580 mm/memory.c:2104
exit_mmap+0x240/0xb40 mm/mmap.c:1280
__mmput+0x118/0x430 kernel/fork.c:1148
exit_mm+0x1da/0x2c0 kernel/exit.c:582
do_exit+0x648/0x2300 kernel/exit.c:954
do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
__do_sys_exit_group kernel/exit.c:1118 [inline]
__se_sys_exit_group kernel/exit.c:1116 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1116
x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fba1d58ec29
Code: Unable to access opcode bytes at 0x7fba1d58ebff.
RSP: 002b:00007ffd85fe6888 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fba1d58ec29
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd85fe68ec R08: 0000001e85fe697f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000120
R13: 00000000000927c0 R14: 00000000000654e0 R15: 00007ffd85fe6940
rcu: rcu_preempt kthread starved for 10494 jiffies! g37721 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5360 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7046 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7061
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+0x4bc/0x870 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: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 36 79 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 e1 74 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 c5 74
RSP: 0018:ffffc90000117640 EFLAGS: 00000293
RAX: ffffffff81b4645b RBX: 1ffff110170c8441 RCX: ffff88801d285ac0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900001177c0 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce
R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff8880b8642208
R13: dffffc0000000000 R14: ffff8880b873b200 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125ae7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555cf9f5c8 CR3: 000000000e138000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2713 [inline]
smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2923
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:852
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245