rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6285/2:b..l
rcu: (detected by 1, t=10503 jiffies, g=16721, q=871244 ncpus=2)
task:syz.3.130 state:R running task stack:23912 pid:6285 tgid:6285 ppid:5854 task_flags:0x20400040 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 fb c2 43 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000ab6ea38 EFLAGS: 00000206
RAX: c2672f2a78d4f300 RBX: 0000000000000000 RCX: c2672f2a78d4f300
RDX: 0000000000000000 RSI: ffffffff8de563b2 RDI: ffffffff8c04ce00
RBP: ffffffff81730195 R08: 0000000000000000 R09: ffffffff81730195
R10: ffffc9000ab6ebf8 R11: ffffffff81ac8020 R12: 0000000000000002
R13: ffffffff8e539f20 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
__call_rcu_common kernel/rcu/tree.c:3123 [inline]
call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243
slab_free_hook mm/slub.c:2381 [inline]
slab_free mm/slub.c:4680 [inline]
kmem_cache_free+0x309/0x400 mm/slub.c:4782
blk_update_request+0x57e/0xe60 block/blk-mq.c:989
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1151
nullb_complete_cmd drivers/block/null_blk/main.c:1402 [inline]
null_handle_cmd drivers/block/null_blk/main.c:1454 [inline]
null_queue_rq+0xbfe/0xe30 drivers/block/null_blk/main.c:1693
null_queue_rqs+0x123/0x270 drivers/block/null_blk/main.c:1707
__blk_mq_flush_list block/blk-mq.c:2828 [inline]
blk_mq_dispatch_queue_requests+0x414/0x800 block/blk-mq.c:2873
blk_mq_flush_plug_list+0x432/0x550 block/blk-mq.c:2961
blk_add_rq_to_plug+0x175/0x450 block/blk-mq.c:1390
blk_mq_submit_bio+0xbcb/0x2520 block/blk-mq.c:3212
__submit_bio+0x207/0x5a0 block/blk-core.c:635
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x4ab/0xb50 block/blk-core.c:751
__block_write_full_folio+0x810/0xe10 fs/buffer.c:1933
blkdev_writepages+0xd1/0x170 block/fops.c:483
do_writepages+0x32b/0x550 mm/page-writeback.c:2634
filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
__filemap_fdatawrite_range mm/filemap.c:419 [inline]
filemap_write_and_wait_range+0x21f/0x320 mm/filemap.c:691
filemap_write_and_wait include/linux/pagemap.h:68 [inline]
sync_blockdev block/bdev.c:260 [inline]
bdev_release+0x192/0x650 block/bdev.c:1126
blkdev_release+0x15/0x20 block/fops.c:699
__fput+0x44c/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1fc1b8e9a9
RSP: 002b:00007ffeeaa8d898 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f1fc1db7ba0 RCX: 00007f1fc1b8e9a9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f1fc1db7ba0 R08: 0000000000000b2c R09: 00000012eaa8db8f
R10: 00000000003ff2b0 R11: 0000000000000246 R12: 0000000000022db1
R13: 00007ffeeaa8d990 R14: ffffffffffffffff R15: 00007ffeeaa8d9b0
rcu: rcu_preempt kthread starved for 254 jiffies! g16721 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:27432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 6.16.0-next-20250731-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: wg-kex-wg2 wg_packet_handshake_receive_worker
RIP: 0010:stack_trace_consume_entry+0xe4/0x280 kernel/stacktrace.c:93
Code: 00 49 89 d9 4c 8b 04 24 4c 89 e2 4c 89 ff 48 8b 74 24 08 48 8b 1f 45 8d 79 01 0f b6 44 15 00 84 c0 0f 85 3a 01 00 00 45 89 38 <4e> 8d 3c cb 4c 89 f8 48 c1 e8 03 80 3c 10 00 74 1a 4c 89 ff 48 89
RSP: 0018:ffffc90000006b58 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90000006ce0 RCX: 5cacd7831c87e200
RDX: dffffc0000000000 RSI: ffffffff8223196e RDI: ffffc90000006c60
RBP: 1ffff92000000d8e R08: ffffc90000006c70 R09: 0000000000000000
R10: ffffc90000006bf8 R11: ffffffff81ac8020 R12: 0000000000000000
R13: 1ffff92000000d8d R14: ffffc90000006c68 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88812580a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555583ca35c8 CR3: 00000000777c8000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x110/0x150 arch/x86/kernel/stacktrace.c:27
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:330 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4180 [inline]
slab_alloc_node mm/slub.c:4229 [inline]
kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4236
kmem_alloc_batch lib/debugobjects.c:371 [inline]
fill_pool+0x100/0x570 lib/debugobjects.c:403
debug_objects_fill_pool lib/debugobjects.c:725 [inline]
debug_object_activate+0x383/0x420 lib/debugobjects.c:814
debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
__call_rcu_common kernel/rcu/tree.c:3108 [inline]
call_rcu+0xaa/0x9c0 kernel/rcu/tree.c:3243
refdst_drop include/net/dst.h:263 [inline]
skb_dst_drop include/net/dst.h:275 [inline]
skb_release_head_state+0x71/0x250 net/core/skbuff.c:1135
skb_release_all net/core/skbuff.c:1149 [inline]
__kfree_skb net/core/skbuff.c:1165 [inline]
consume_skb+0x60/0xf0 net/core/skbuff.c:1397
nft_synproxy_eval_v4+0x376/0x560 net/netfilter/nft_synproxy.c:60
nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc2/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:5979 [inline]
__netif_receive_skb+0x143/0x380 net/core/dev.c:6092
process_backlog+0x60e/0x14f0 net/core/dev.c:6444
__napi_poll+0xc7/0x360 net/core/dev.c:7497
napi_poll net/core/dev.c:7560 [inline]
net_rx_action+0x707/0xe30 net/core/dev.c:7687
handle_softirqs+0x283/0x870 kernel/softirq.c:579
do_softirq+0xec/0x180 kernel/softirq.c:480
__local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
local_bh_enable include/linux/bottom_half.h:33 [inline]
fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline]
kernel_fpu_end+0xd2/0x120 arch/x86/kernel/fpu/core.c:479
blake2s_compress+0x5f/0xd0 lib/crypto/x86/blake2s-glue.c:46
blake2s_final+0x116/0x260 lib/crypto/blake2s.c:55
hmac+0x1c6/0x330 drivers/net/wireguard/noise.c:325
kdf+0x182/0x270 drivers/net/wireguard/noise.c:375
mix_precomputed_dh drivers/net/wireguard/noise.c:426 [inline]
wg_noise_handshake_consume_initiation+0x3ee/0x900 drivers/net/wireguard/noise.c:623
wg_receive_handshake_packet drivers/net/wireguard/receive.c:144 [inline]
wg_packet_handshake_receive_worker+0x5f2/0xfb0 drivers/net/wireguard/receive.c:213
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245