rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P25019/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=178501, q=1220 ncpus=1)
task:udevd state:R running task stack:26504 pid:25019 tgid:25019 ppid:5201 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872
Code: bb 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 a2 63 ef 0e 0f 82 74 02 00 00 8b 35 1a 94 ef 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 b9 ba 18 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0018:ffffc9000491f238 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c9520 RCX: 00000000ea3541df
RDX: 0000000000000000 RSI: ffffffff8daa494a RDI: ffffffff8bf2b580
RBP: 0000000000000002 R08: 000000008fc65610 R09: 0000000008fc6561
R10: 0000000000000002 R11: ffff888028880b30 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6670 [inline]
kfree+0x2f8/0x6e0 mm/slub.c:6878
tomoyo_realpath_from_path+0x19f/0x6e0 security/tomoyo/realpath.c:286
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x2ab/0x3c0 security/tomoyo/file.c:771
tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334
security_file_open+0x84/0x1e0 security/security.c:2636
do_dentry_open+0x597/0x1590 fs/open.c:939
vfs_open+0x82/0x3f0 fs/open.c:1094
do_open fs/namei.c:4628 [inline]
path_openat+0x2078/0x3140 fs/namei.c:4787
do_filp_open+0x20b/0x470 fs/namei.c:4814
do_sys_openat2+0x121/0x290 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_openat fs/open.c:1452 [inline]
__se_sys_openat fs/open.c:1447 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1447
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f21430a7407
RSP: 002b:00007ffe03c65360 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f214378a880 RCX: 00007f21430a7407
RDX: 00000000000a0241 RSI: 00007ffe03c66020 RDI: ffffffffffffff9c
RBP: 000055780a116fc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000124 R11: 0000000000000202 R12: 000055780a0d5830
R13: 00007ffe03c66020 R14: 00007ffe03c65c20 R15: 00007ffe03c65820
rcu: rcu_preempt kthread starved for 993 jiffies! g178501 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:28288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 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:
CPU: 1 UID: 0 PID: 12407 Comm: kworker/u8:44 Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872
Code: bb 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 a2 63 ef 0e 0f 82 74 02 00 00 8b 35 1a 94 ef 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 b9 ba 18 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0018:ffffc90000a081d0 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c9520 RCX: 00000000bf3fbf97
RDX: 0000000000000000 RSI: ffffffff8daa494a RDI: ffffffff8bf2b580
RBP: 0000000000000002 R08: 00000000ac0d5af0 R09: 000000000ac0d5af
R10: 0000000000000002 R11: ffff88801c79c830 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881249fc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556b6cb5c8 CR3: 000000003e0f8000 CR4: 00000000003526f0
Call Trace:
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
__skb_ext_alloc+0x1a/0x80 net/core/skbuff.c:7023
skb_ext_add+0x242/0x7b0 net/core/skbuff.c:7127
nf_bridge_alloc include/net/netfilter/br_netfilter.h:12 [inline]
br_nf_pre_routing_ipv6+0xca/0x8c0 net/bridge/br_netfilter_ipv6.c:172
br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0xb28/0x14e0 net/bridge/br_input.c:442
__netif_receive_skb_core.constprop.0+0x6b3/0x35b0 net/core/dev.c:6024
__netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6135
__netif_receive_skb+0x1d/0x160 net/core/dev.c:6250
process_backlog+0x4a2/0x1650 net/core/dev.c:6602
__napi_poll.constprop.0+0xb3/0x540 net/core/dev.c:7666
napi_poll net/core/dev.c:7729 [inline]
net_rx_action+0x9f9/0xfa0 net/core/dev.c:7881
handle_softirqs+0x219/0x950 kernel/softirq.c:622
do_softirq kernel/softirq.c:523 [inline]
do_softirq+0xb2/0xf0 kernel/softirq.c:510
__local_bh_enable_ip+0x100/0x120 kernel/softirq.c:450
local_bh_enable include/linux/bottom_half.h:33 [inline]
fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline]
kernel_fpu_end arch/x86/kernel/fpu/core.c:480 [inline]
kernel_fpu_end+0x5e/0x70 arch/x86/kernel/fpu/core.c:473
blake2s_compress+0x77/0xe0 lib/crypto/x86/blake2s.h:42
blake2s_final+0xc9/0x150 lib/crypto/blake2s.c:142
hmac.constprop.0+0x252/0x420 drivers/net/wireguard/noise.c:325
kdf.constprop.0+0x122/0x280 drivers/net/wireguard/noise.c:360
message_ephemeral+0x5f/0x70 drivers/net/wireguard/noise.c:493
wg_noise_handshake_create_initiation+0x322/0x610 drivers/net/wireguard/noise.c:545
wg_packet_send_handshake_initiation+0x19a/0x360 drivers/net/wireguard/send.c:34
wg_packet_handshake_send_worker+0x1c/0x30 drivers/net/wireguard/send.c:51
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246