rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=1034/1/0x4000000000000000 softirq=58549/58557 fqs=1
rcu: (detected by 1, t=10503 jiffies, g=62485, q=286 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 11484 Comm: syz.6.1771 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__rcu_read_unlock+0xa/0xe0 kernel/rcu/tree_plugin.h:431
Code: dc 48 89 df e8 17 8a 85 00 eb d2 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 <41> 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3d 49 8c 8c 11 48
RSP: 0018:ffffc90000007cf0 EFLAGS: 00000086
RAX: 540b778a13c09c00 RBX: ffffffff89b6d35b RCX: 0000000000010000
RDX: 0000000000000001 RSI: ffffffff8e215bb3 RDI: ffffffff8c28b760
RBP: 0000000000000001 R08: ffff88805012719f R09: 1ffff1100a024e33
R10: dffffc0000000000 R11: ffffed100a024e34 R12: ffff888048f65000
R13: ffff888050127000 R14: ffff888048f65400 R15: 18b39122717ee40f
FS: 0000000000000000(0000) GS:ffff88812529f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2ded86 CR3: 000000000e74a000 CR4: 0000000000350ef0
Call Trace:
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
advance_sched+0xacb/0xc20 net/sched/sch_taprio.c:994
__run_hrtimer kernel/time/hrtimer.c:1930 [inline]
__hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994
hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:202 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:232 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:folio_test_swapbacked include/linux/page-flags.h:572 [inline]
RIP: 0010:folio_test_swapcache include/linux/page-flags.h:627 [inline]
RIP: 0010:free_swap_cache+0x63/0x300 mm/swap_state.c:363
Code: 08 00 4d 8b 3e 4c 89 fe 48 83 e6 01 31 ff e8 74 a4 9d ff 49 83 e7 01 0f 85 46 02 00 00 48 89 df be 08 00 00 00 e8 ed f7 08 00 <49> 89 df 49 c1 ef 03 43 80 3c 27 00 74 08 48 89 df e8 67 f5 08 00
RSP: 0018:ffffc90003d2f2a8 EFLAGS: 00000256
RAX: ffffffff82281801 RBX: ffffea00004a23c0 RCX: ffffffff82281853
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffea00004a23c0
RBP: ffffc90003d2f568 R08: ffffea00004a23c7 R09: 1ffffd4000094478
R10: dffffc0000000000 R11: fffff94000094479 R12: dffffc0000000000
R13: 1ffffd4000094479 R14: ffffea00004a23c8 R15: 0000000000000000
free_pages_and_swap_cache+0x1ba/0x490 mm/swap_state.c:394
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:417 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:424
zap_pte_range mm/memory.c:1973 [inline]
zap_pmd_range mm/memory.c:2020 [inline]
zap_pud_range mm/memory.c:2048 [inline]
zap_p4d_range mm/memory.c:2069 [inline]
__zap_vma_range+0x3de2/0x4b70 mm/memory.c:2109
unmap_vmas+0x3ac/0x570 mm/memory.c:2178
exit_mmap+0x280/0x9e0 mm/mmap.c:1300
__mmput+0x118/0x430 kernel/fork.c:1178
exit_mm+0x1f6/0x2d0 kernel/exit.c:582
do_exit+0x6a2/0x22c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1119
__do_sys_exit_group kernel/exit.c:1130 [inline]
__se_sys_exit_group kernel/exit.c:1128 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1128
x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f75fc99ce59
Code: Unable to access opcode bytes at 0x7f75fc99ce2f.
RSP: 002b:00007ffcd89a5678 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f75fc99ce59
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffcd89a56dc R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000000df
R13: 00000000000927c0 R14: 0000000000054d3f R15: 00007ffcd89a5730
rcu: rcu_preempt kthread starved for 10501 jiffies! g62485 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 149 Comm: kworker/u8:7 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xfd4/0x13d0 kernel/smp.c:892
Code: 89 ee 83 e6 01 31 ff e8 9a 07 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 45 03 0c 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 2a 03 0c 00 eb e5 44 89
RSP: 0018:ffffc90002e3f700 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b873c188 RCX: ffff88801f3f8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002e3f840 R08: ffffffff90301cf7 R09: 1ffffffff206039e
R10: dffffc0000000000 R11: fffffbfff206039f R12: 1ffff110170c8591
R13: dffffc0000000000 R14: ffff8880b8642c88 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812539f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7c4707a6b0 CR3: 000000000e74a000 CR4: 0000000000350ef0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057
on_each_cpu include/linux/smp.h:72 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate+0xab/0x290 mm/kfence/core.c:906
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245