rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9536/1:b..l P5632/1:b..l rcu: (detected by 1, t=10505 jiffies, g=45597, q=370597 ncpus=2) task:syz-executor state:R running task stack:21568 pid:5632 tgid:5632 ppid:5618 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893 Code: 7d ca 11 00 00 00 00 eb b5 e8 c5 0d 2e 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 b5 38 ca 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 85 59 6d ff cc 48 8d 3d 12 3d b8 RSP: 0018:ffffc900046a7308 EFLAGS: 00000282 RAX: 64722e7f7024ba00 RBX: 0000000000000206 RCX: 0000000000000046 RDX: 0000000000000002 RSI: ffffffff8e4b276c RDI: ffffffff8c4bdd80 RBP: ffff8880352a8bf0 R08: ffffc900046a7cf8 R09: ffffc900046a7438 R10: dffffc0000000000 R11: fffff520008d4e89 R12: 0000000000000002 R13: 0000000000000002 R14: ffffffff8eb59c60 R15: ffff8880352a8000 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950 __slab_free+0x274/0x2c0 mm/slub.c:5741 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_noprof+0x375/0x720 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 security_inode_getattr+0x12b/0x310 security/security.c:1895 vfs_getattr+0x23/0x70 fs/stat.c:259 vfs_statx_path+0x2b/0x230 fs/stat.c:299 vfs_statx+0x12e/0x200 fs/stat.c:356 vfs_fstatat+0x11b/0x170 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:538 [inline] __se_sys_newfstatat fs/stat.c:532 [inline] __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efd72f9c4da RSP: 002b:00007ffe774d0ac8 EFLAGS: 00000286 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007efd72f9c4da RDX: 00007ffe774d0af0 RSI: 00007ffe774d0b80 RDI: 00000000ffffff9c RBP: 00007ffe774d0b80 R08: 00007ffe774d1b80 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000286 R12: 00007ffe774d1c10 R13: 00007efd7303330a R14: 00000000000492f6 R15: 00007ffe774d1c50 task:dhcpcd-run-hook state:R running task stack:26600 pid:9536 tgid:9536 ppid:9531 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:memset+0xf/0x30 arch/x86/lib/memset_64.S:38 Code: 44 88 1f e9 8e 24 3f f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 e9 62 24 3f f5 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc900065bf118 EFLAGS: 00000202 RAX: ffffc900065bf500 RBX: ffffc900065bf218 RCX: 000000000000000f RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc900065bf219 RBP: 1ffffffff21f9e9e R08: ffffc900065bf227 R09: ffffc900065bf218 R10: dffffc0000000000 R11: fffff52000cb7e45 R12: dffffc0000000000 R13: ffffffff90fcf4ee R14: ffffc900065bf1c8 R15: ffffc900065bf210 unwind_next_frame+0xd04/0x2550 arch/x86/kernel/unwind_orc.c:621 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950 __slab_free+0x274/0x2c0 mm/slub.c:5741 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4584 [inline] slab_alloc_node mm/slub.c:4917 [inline] __do_kmalloc_node mm/slub.c:5333 [inline] __kmalloc_noprof+0x311/0x720 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2739 do_dentry_open+0x4a0/0x1380 fs/open.c:924 vfs_open+0x3b/0x340 fs/open.c:1052 do_open fs/namei.c:4700 [inline] path_openat+0x2e44/0x3830 fs/namei.c:4863 do_file_open+0x23e/0x4a0 fs/namei.c:4892 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1385 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe25d26fc3a RSP: 002b:00007fff4af243c8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe25d26fc3a RDX: 0000000000090800 RSI: 000055b9d600fe10 RDI: 00000000ffffff9c RBP: 000055b9d600d50f R08: 00007fe25d34bac0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 00007fff4af24528 R13: 000055b9d600d508 R14: 0000000000000001 R15: 000055b9d600fe37 rcu: rcu_preempt kthread starved for 673 jiffies! g45597 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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: 10 Comm: kworker/0:1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: wg-crypt-wg0 wg_packet_decrypt_worker RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x17/0xb0 kernel/rcu/tree.c:752 Code: 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 10 42 c1 11 e8 db 33 25 0a 89 c3 <83> f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 b7 4f RSP: 0018:ffffc90000006e58 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000080000102 RDX: ffffc90000006f01 RSI: ffffffff8c4bdd60 RDI: ffffffff8c4bdd20 RBP: 1ffffffff22ef901 R08: ffffc90000007430 R09: ffffc90000006fd8 R10: dffffc0000000000 R11: fffff52000000dfd R12: ffffc90000000000 R13: ffffffff8177827f R14: ffffffff8eb59c60 R15: ffffc90000007440 FS: 0000000000000000(0000) GS:ffff888124f4e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f41d06da008 CR3: 0000000058f92000 CR4: 0000000000350ef0 Call Trace: trace_lock_release include/trace/events/lock.h:68 [inline] lock_release+0x4b/0x3c0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x1c5/0x640 mm/slub.c:6692 skb_kfree_head net/core/skbuff.c:1077 [inline] skb_free_head net/core/skbuff.c:1089 [inline] skb_release_data+0x85e/0xab0 net/core/skbuff.c:1116 skb_release_all net/core/skbuff.c:1191 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1205 nft_synproxy_eval_v4+0x36a/0x4e0 net/netfilter/nft_synproxy.c:-1 nft_synproxy_do_eval+0x335/0x550 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1b10 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6212 [inline] __netif_receive_skb net/core/dev.c:6325 [inline] process_backlog+0xa34/0x1860 net/core/dev.c:6676 __napi_poll+0xaa/0x330 net/core/dev.c:7735 napi_poll net/core/dev.c:7798 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:7955 handle_softirqs+0x225/0x840 kernel/softirq.c:622 do_softirq+0x76/0xd0 kernel/softirq.c:523 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] ptr_ring_consume_bh include/linux/ptr_ring.h:393 [inline] wg_packet_decrypt_worker+0x2ae/0xda0 drivers/net/wireguard/receive.c:499 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245