rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=964c/1/0x4000000000000000 softirq=30482/30496 fqs=1
rcu: (detected by 0, t=10502 jiffies, g=23857, q=418 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6829 Comm: udevd Not tainted 6.15.0-syzkaller-01972-g914873bc7df9 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:107 [inline]
RIP: 0010:raw_atomic_try_cmpxchg_acquire include/linux/atomic/atomic-arch-fallback.h:2170 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1302 [inline]
RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
RIP: 0010:do_raw_spin_lock+0x12e/0x290 kernel/locking/spinlock_debug.c:116
Code: 00 48 89 df be 04 00 00 00 e8 8e 1a 82 00 48 8d 7c 24 40 be 04 00 00 00 e8 7f 1a 82 00 8b 44 24 40 b9 01 00 00 00 f0 0f b1 0b <0f> 85 dd 00 00 00 65 8b 1d e9 19 d7 10 48 b9 00 00 00 00 00 fc ff
RSP: 0018:ffffc90000a08be0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff8880b8927ac0 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000a08c20
RBP: ffffc90000a08c90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000141184 R12: ffff8880b8927ad0
R13: ffff8880b8927ac8 R14: 1ffff11017124f5a R15: 1ffff11017124f59
FS: 00007fc7e2460880(0000) GS:ffff8881261c7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f76f7d81c78 CR3: 0000000054cf8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:120 [inline]
_raw_spin_lock_irq+0xae/0xf0 kernel/locking/spinlock.c:170
__run_hrtimer kernel/time/hrtimer.c:1765 [inline]
__hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x83/0x90 kernel/kcov.c:316
Code: 8d 52 28 4d 39 ca 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 08 c2 99 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90005247720 EFLAGS: 00000293
RAX: ffffffff82371cfc RBX: ffff888022a73548 RCX: 0000000000000000
RDX: ffff888025505a00 RSI: 00000000ffffffff RDI: 0000000000000000
RBP: 00000000ffffffff R08: 0000000000000000 R09: ffffffff82371a47
R10: dffffc0000000000 R11: ffffed1006294418 R12: 1ffff92000a48f00
R13: ffff8880314a2000 R14: ffff888022a73490 R15: dffffc0000000000
fast_dput+0x2c/0x430 fs/dcache.c:826
dput+0xe8/0x2b0 fs/dcache.c:905
step_into+0x34d/0xf30 fs/namei.c:1991
walk_component fs/namei.c:2144 [inline]
link_path_walk+0x77b/0xea0 fs/namei.c:2506
path_openat+0x28c/0x3830 fs/namei.c:4042
do_filp_open+0x1fa/0x410 fs/namei.c:4073
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x220 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc7e1ca7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffe3a5ea130 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc7e2460880 RCX: 00007fc7e1ca7407
RDX: 00000000000a0241 RSI: 00007ffe3a5eadf0 RDI: ffffffffffffff9c
RBP: 0000560c38f66950 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000124 R11: 0000000000000202 R12: 0000560c38f54710
R13: 00007ffe3a5eadf0 R14: 00007ffe3a5ea9f0 R15: 00007ffe3a5ea5f0
rcu: rcu_preempt kthread starved for 10500 jiffies! g23857 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:27392 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5392 [inline]
__schedule+0x16a2/0x4cb0 kernel/sched/core.c:6781
__schedule_loop kernel/sched/core.c:6859 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6874
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 65 Comm: kworker/u8:4 Not tainted 6.15.0-syzkaller-01972-g914873bc7df9 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0xe69/0x11c0 kernel/smp.c:885
Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 b0 6f 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 5b 6b 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 40 6b 0b
RSP: 0018:ffffc9000216f740 EFLAGS: 00000293
RAX: ffffffff81b46890 RBX: ffff8880b883b000 RCX: ffff88801bf89e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000216f8a0 R08: ffffffff8f7e98b7 R09: 1ffffffff1efd316
R10: dffffc0000000000 R11: fffffbfff1efd317 R12: 1ffff11017127ef1
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b893f788
FS: 0000000000000000(0000) GS:ffff8881260c7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000009e1000 CR3: 000000000dd36000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2660 [inline]
smp_text_poke_batch_finish+0x5e0/0x1100 arch/x86/kernel/alternative.c:2870
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:850
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245