rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6543/1:b..l
rcu: (detected by 1, t=10505 jiffies, g=15681, q=2192 ncpus=2)
task:udevd state:R running task stack:28088 pid:6543 tgid:6543 ppid:5196 task_flags:0x400140 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x14ea/0x5050 kernel/sched/core.c:6867
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7051
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
wp_page_copy mm/memory.c:3823 [inline]
do_wp_page+0x4207/0x5990 mm/memory.c:4183
handle_pte_fault mm/memory.c:6292 [inline]
__handle_mm_fault mm/memory.c:6414 [inline]
handle_mm_fault+0x1520/0x32a0 mm/memory.c:6583
do_user_addr_fault+0xa73/0x1360 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x555fa3f8bf7d
RSP: 002b:00007ffc6a89fff0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000555fc5d24e20 RCX: 0000000000000044
RDX: 00007ffc6a8a41b4 RSI: 0000000000004000 RDI: 00007ffc6a89fff0
RBP: 00007ffc6a89fff0 R08: 0000555fc5d21a10 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffc6a8a4178
R13: 00000000000000c6 R14: 00007ffc6a8a41b4 R15: 0000000000000000
rcu: rcu_preempt kthread timer wakeup didn't happen for 5128 jiffies! g15681 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=7329
rcu: rcu_preempt kthread starved for 5129 jiffies! g15681 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28000 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x14ea/0x5050 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 kernel/sched/core.c:6964
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x1560 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:2285
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 981 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Workqueue: wg-kex-wg0 wg_packet_handshake_receive_worker
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:__lock_acquire+0xa54/0x2cf0 kernel/locking/lockdep.c:5234
Code: c7 c6 fc 3a de 8d 67 48 0f b9 3a 90 31 c0 48 83 78 40 00 0f 84 5f 1d 00 00 41 8b 45 20 25 ff 1f 00 00 48 0f a3 05 4c 29 5a 12 <73> 10 48 69 c0 c8 00 00 00 48 8d 80 b0 83 9b 93 eb 32 83 3d 13 b9
RSP: 0018:ffffc90000007ac0 EFLAGS: 00000047
RAX: 0000000000000000 RBX: 000000002cd708a8 RCX: 00000000d08d4db1
RDX: 00000000d890a6cc RSI: 00000000e3c36222 RDI: ffff888025881e80
RBP: cc889bfc00000000 R08: ffffffff84aabbfc R09: ffffffff9a2c94f0
R10: ffff888079661300 R11: ffffed100f2cc263 R12: ffff888025882a50
R13: ffff888025882a50 R14: ffff888025881e80 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff8881256f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f76a10f6000 CR3: 0000000021b1a000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
debug_object_deactivate+0x6c/0x3a0 lib/debugobjects.c:873
debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
debug_deactivate+0x1d/0x1e0 kernel/time/hrtimer.c:483
__run_hrtimer kernel/time/hrtimer.c:1745 [inline]
__hrtimer_run_queues+0x2bc/0xc30 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x42b/0x1010 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x3d0 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:fmul2 lib/crypto/x86/curve25519.h:291 [inline]
RIP: 0010:point_add_and_double lib/crypto/x86/curve25519.h:1001 [inline]
RIP: 0010:montgomery_ladder lib/crypto/x86/curve25519.h:1093 [inline]
RIP: 0010:curve25519_ever64 lib/crypto/x86/curve25519.h:1247 [inline]
RIP: 0010:curve25519_arch lib/crypto/x86/curve25519.h:1594 [inline]
RIP: 0010:curve25519+0x1fb7/0x51d0 lib/crypto/curve25519.c:44
Code: 49 0f 38 f6 c0 49 89 47 78 4c 89 f9 4d 89 e7 48 c7 c2 26 00 00 00 c4 62 bb f6 69 20 31 ff f3 4c 0f 38 f6 01 c4 e2 b3 f6 59 28 <66> 4d 0f 38 f6 cd f3 4c 0f 38 f6 49 08 c4 62 ab f6 69 30 66 4c 0f
RSP: 0018:ffffc90003817120 EFLAGS: 00000246
RAX: 7fdeaf870f436aa8 RBX: 000000000000000b RCX: ffffc900038171c0
RDX: 0000000000000026 RSI: ffffc900038172a0 RDI: 0000000000000000
RBP: ffffc90003817470 R08: bc485c50c91c1bd8 R09: 463286eaa1303332
R10: 1ec1b6ee3189bbb6 R11: 39793234997b3870 R12: ffffc90003817320
R13: 000000000000000e R14: 255a70b05127bc05 R15: ffffc90003817320
mix_dh drivers/net/wireguard/noise.c:411 [inline]
wg_noise_handshake_consume_initiation+0x245/0x9a0 drivers/net/wireguard/noise.c:608
wg_receive_handshake_packet drivers/net/wireguard/receive.c:144 [inline]
wg_packet_handshake_receive_worker+0x674/0x10c0 drivers/net/wireguard/receive.c:213
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246