rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18750/2:b..l rcu: (detected by 1, t=10503 jiffies, g=95057, q=1369171 ncpus=2) task:syz.5.2575 state:R running task stack:23688 pid:18750 tgid:18743 ppid:9259 task_flags:0x40054c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7104 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:107 [inline] RIP: 0010:raw_atomic_try_cmpxchg include/linux/atomic/atomic-arch-fallback.h:2130 [inline] RIP: 0010:raw_atomic_fetch_add_unless include/linux/atomic/atomic-arch-fallback.h:2431 [inline] RIP: 0010:raw_atomic_add_unless include/linux/atomic/atomic-arch-fallback.h:2456 [inline] RIP: 0010:atomic_add_unless include/linux/atomic/atomic-instrumented.h:1518 [inline] RIP: 0010:page_ref_add_unless.constprop.0+0xc4/0x390 include/linux/page_ref.h:238 Code: 5b 34 e8 9f 4d c8 ff 31 ff 89 de 41 89 dd e8 d3 48 c8 ff 85 db 0f 84 9f 01 00 00 e8 86 4d c8 ff 8d 53 01 89 d8 f0 0f b1 55 00 <41> 0f 94 c4 31 ff 89 c3 44 89 e6 e8 4c 48 c8 ff 45 84 e4 74 c3 e8 RSP: 0018:ffffc900032772d0 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81f37c4d RDX: 0000000000000002 RSI: ffffffff81f37c5a RDI: 0000000000000005 RBP: ffffea0001406b34 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 1ffff9200064ee68 R13: 0000000000000001 R14: fffffffffffffffe R15: 0000000000000000 folio_ref_add_unless include/linux/page_ref.h:248 [inline] folio_try_get include/linux/page_ref.h:264 [inline] find_get_entry mm/filemap.c:2039 [inline] find_lock_entries+0x1c1/0xbd0 mm/filemap.c:2129 shmem_undo_range+0x216/0x1150 mm/shmem.c:1107 shmem_truncate_range mm/shmem.c:1237 [inline] shmem_evict_inode+0x3a1/0xbe0 mm/shmem.c:1365 evict+0x3e6/0x920 fs/inode.c:810 iput_final fs/inode.c:1898 [inline] iput fs/inode.c:1924 [inline] iput+0x521/0x880 fs/inode.c:1910 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:466 __dentry_kill+0x1d0/0x600 fs/dcache.c:669 dput.part.0+0x4b1/0x9b0 fs/dcache.c:911 dput+0x1f/0x30 fs/dcache.c:901 __fput+0x51c/0xb70 fs/file_table.c:473 task_work_run+0x150/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xae2/0x2c70 kernel/exit.c:959 do_group_exit+0xd3/0x2a0 kernel/exit.c:1108 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f830ed8e969 RSP: 002b:00007f830fb4d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f830efb6168 RCX: 00007f830ed8e969 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f830efb6168 RBP: 00007f830efb6160 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f830efb616c R13: 0000000000000000 R14: 00007ffc27c89f50 R15: 00007ffc27c8a038 rcu: rcu_preempt kthread starved for 219 jiffies! g95057 f0x2 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:28536 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6874 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 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: 1 UID: 0 PID: 11548 Comm: kworker/u8:16 Not tainted 6.15.0-syzkaller-08486-gf66bc387efbe #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker RIP: 0010:get_stack_info_noinstr+0x28/0x120 arch/x86/kernel/dumpstack_64.c:176 Code: 90 90 66 0f 1f 00 41 55 41 54 49 89 fc 55 48 89 d5 53 48 89 f3 e8 18 01 00 00 84 c0 0f 85 90 00 00 00 65 48 8b 15 90 4b 2f 08 <48> 39 d3 74 0b 5b 5d 41 5c 41 5d e9 48 26 03 00 48 c7 c7 0b 6f c0 RSP: 0018:ffffc90000a08118 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888027154880 RCX: ffffc90005898000 RDX: ffff888027154880 RSI: ffff888027154880 RDI: ffffc90000a08168 RBP: ffffc90000a081b8 R08: 0000000000000001 R09: 0000000000000000 R10: ffffc90000a081b8 R11: 0000000000000001 R12: ffffc90000a08168 R13: ffffc90000a081d8 R14: ffffc90000a081b8 R15: ffffc90000a081e0 FS: 0000000000000000(0000) GS:ffff888124a71000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31514ff8 CR3: 0000000030338000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: get_stack_info+0x30/0xa0 arch/x86/kernel/dumpstack_64.c:199 __unwind_start+0x3f6/0x7f0 arch/x86/kernel/unwind_orc.c:727 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2380 [inline] slab_free mm/slub.c:4642 [inline] kmem_cache_free+0x2d1/0x4d0 mm/slub.c:4744 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1110 __kfree_skb net/core/skbuff.c:1167 [inline] consume_skb net/core/skbuff.c:1398 [inline] consume_skb+0xcc/0x100 net/core/skbuff.c:1392 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:60 [inline] nft_synproxy_do_eval+0xa6b/0xd80 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x2e9/0x1920 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x18a/0x340 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:623 nf_hook.constprop.0+0x422/0x750 include/linux/netfilter.h:272 NF_HOOK include/linux/netfilter.h:315 [inline] ip_local_deliver+0x169/0x1f0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:469 [inline] ip_rcv_finish net/ipv4/ip_input.c:447 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] NF_HOOK include/linux/netfilter.h:311 [inline] ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:567 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:5977 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6090 process_backlog+0x442/0x15e0 net/core/dev.c:6442 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7414 napi_poll net/core/dev.c:7478 [inline] net_rx_action+0xa9f/0xfe0 net/core/dev.c:7605 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579 do_softirq kernel/softirq.c:480 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:467 __local_bh_enable_ip+0x100/0x120 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+0x5e/0x70 arch/x86/kernel/fpu/core.c:476 poly1305_blocks_arch+0x66/0xf0 arch/x86/lib/crypto/poly1305_glue.c:80 poly1305_blocks lib/crypto/poly1305.c:36 [inline] poly1305_update+0x12e/0x2d0 lib/crypto/poly1305.c:44 __chacha20poly1305_encrypt+0x20f/0x320 lib/crypto/chacha20poly1305.c:81 chacha20poly1305_encrypt+0x479/0x640 lib/crypto/chacha20poly1305.c:104 message_encrypt drivers/net/wireguard/noise.c:467 [inline] wg_noise_handshake_create_initiation+0x33b/0x650 drivers/net/wireguard/noise.c:555 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+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245