rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=16fc/1/0x4000000000000000 softirq=65548/65549 fqs=2
rcu: (detected by 1, t=10506 jiffies, g=61181, q=31 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15169 Comm: syz.7.2017 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x3a/0xb0 kernel/rcu/tree.c:752
Code: e8 bb 8e b7 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 4d bc 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 ec c0 80 00 48 c7 c3 58 a7 a3 92 49 03 1e 48 89
RSP: 0018:ffffc90000007bd0 EFLAGS: 00000046
RAX: 1ffffffff1b789ba RBX: 0000000000000000 RCX: 0000000000010003
RDX: 0000000000000000 RSI: ffffffff8be09740 RDI: ffffffff8be09700
RBP: ffffffff849a0757 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff52000000f98 R12: 0000000000000000
R13: ffffffff99cd9268 R14: ffffffff8dbc4dd0 R15: dffffc0000000000
FS: 00007fded6bc46c0(0000) GS:ffff888125bf9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc993372a60 CR3: 000000007ef34000 CR4: 00000000003526f0
Call Trace:
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x5f/0x340 kernel/locking/lockdep.c:5831
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
debug_object_activate+0x87/0x540 lib/debugobjects.c:818
debug_hrtimer_activate kernel/time/hrtimer.c:446 [inline]
debug_activate kernel/time/hrtimer.c:485 [inline]
enqueue_hrtimer+0x30/0x380 kernel/time/hrtimer.c:1089
__run_hrtimer kernel/time/hrtimer.c:1802 [inline]
__hrtimer_run_queues+0x636/0xc30 kernel/time/hrtimer.c:1849
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1911
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:path_init+0x0/0x1330 fs/namei.c:2669
Code: 38 c1 7c bb 4c 89 f7 e8 7e a5 e9 ff eb b1 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 70 89 f3 49 89 fd 49 bf 00
RSP: 0018:ffffc9000ec87af8 EFLAGS: 00000283
RAX: ffffffff823cbab0 RBX: ffffc9000ec87c20 RCX: 0000000000080000
RDX: ffffc9000df99000 RSI: 0000000000000101 RDI: ffffc9000ec87c20
RBP: 0000000000000101 R08: ffffc9000ec87c2f R09: 0000000000000000
R10: ffffc9000ec87c20 R11: fffff52001d90f86 R12: ffff888074ea2728
R13: 1ffff92001d90f80 R14: ffff88803b79c100 R15: ffffc9000ec87e60
path_lookupat+0x2a/0x8c0 fs/namei.c:2794
filename_lookup+0x212/0x570 fs/namei.c:2833
user_path_at+0x40/0x160 fs/namei.c:3612
do_mount fs/namespace.c:4159 [inline]
__do_sys_mount fs/namespace.c:4351 [inline]
__se_sys_mount+0x2d4/0x410 fs/namespace.c:4328
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fded5d8f749
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:00007fded6bc4038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fded5fe5fa0 RCX: 00007fded5d8f749
RDX: 0000200000000180 RSI: 0000200000000100 RDI: 0000000000000000
RBP: 00007fded5e13f91 R08: 0000200000000400 R09: 0000000000000000
R10: 0000000002020000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fded5fe6038 R14: 00007fded5fe5fa0 R15: 00007ffd899701b8
rcu: rcu_preempt kthread starved for 10495 jiffies! g61181 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:27680 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5290 [inline]
__schedule+0x14db/0x5030 kernel/sched/core.c:6902
__schedule_loop kernel/sched/core.c:6984 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6999
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297
kthread+0x389/0x480 kernel/kthread.c:467
ret_from_fork+0x510/0xa50 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: 6403 Comm: kworker/u8:21 Not tainted syzkaller #0 PREEMPT(full)
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+0xcc5/0x1260 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b4 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 5f 96 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 43 96
RSP: 0018:ffffc90003647760 EFLAGS: 00000293
RAX: ffffffff81b5835d RBX: 1ffff110170c85c1 RCX: ffff88802aa80000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900036478a0 R08: ffffffff8fa2d9f7 R09: 1ffffffff1f45b3e
R10: dffffc0000000000 R11: fffffbfff1f45b3f R12: ffff8880b8642e08
R13: dffffc0000000000 R14: ffff8880b873bd80 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125cf9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fded6ba2f98 CR3: 000000000df3e000 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:2746 [inline]
smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2956
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+0xad/0x240 mm/kfence/core.c:879
process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
kthread+0x389/0x480 kernel/kthread.c:467
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245