rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2/1:b..l P5611/1:b..l P12285/1:b..l rcu: (detected by 0, t=10502 jiffies, g=64309, q=1839 ncpus=1) task:syz.3.2109 state:R running task stack:26216 pid:12285 tgid:12284 ppid:5601 task_flags:0x40054c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7284 preempt_schedule_common+0x3c/0xb0 kernel/sched/core.c:7463 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:213 spin_unlock include/linux/spinlock.h:401 [inline] zap_pte_range mm/memory.c:2095 [inline] zap_pmd_range mm/memory.c:2151 [inline] zap_pud_range mm/memory.c:2179 [inline] zap_p4d_range mm/memory.c:2200 [inline] __zap_vma_range+0x16b0/0x48e0 mm/memory.c:2240 unmap_vmas+0x299/0x5f0 mm/memory.c:2309 exit_mmap+0x1ef/0xa00 mm/mmap.c:1315 __mmput+0x12a/0x410 kernel/fork.c:1193 mmput+0x67/0x80 kernel/fork.c:1216 exit_mm kernel/exit.c:592 [inline] do_exit+0x83b/0x2a50 kernel/exit.c:974 do_group_exit+0xd5/0x2a0 kernel/exit.c:1129 get_signal+0x1ec7/0x21e0 kernel/signal.c:3112 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1c1ed9e159 RSP: 002b:00007f1c1fbf5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 RAX: 0090000000000002 RBX: 00007f1c1f025fa0 RCX: 00007f1c1ed9e159 RDX: 0000000000000000 RSI: 0090000000000002 RDI: 0000000000000008 RBP: 00007f1c1ee3506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1c1f026038 R14: 00007f1c1f025fa0 R15: 00007ffdd1f4c728 task:syz-executor state:R running task stack:22120 pid:5611 tgid:5611 ppid:5597 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7284 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:7606 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa10 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5947 Code: 05 cf a9 a5 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 de e6 5d 0f 0f 82 c9 02 00 00 8b 35 7e 18 5e 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 6d a9 a5 12 0f 85 09 03 00 00 48 83 c4 RSP: 0018:ffffc900032475c8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000200 RDX: 0000000000000000 RSI: ffffffff8e36912e RDI: ffffffff8c623a80 RBP: ffffffff8edec5a0 R08: 00000000adaccaaf R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000001 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:183 __reset_page_owner+0x84/0x190 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x2cc/0x840 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x276/0x460 security/tomoyo/file.c:827 security_inode_getattr+0x116/0x280 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_fstat+0x4b/0xe0 fs/stat.c:281 __do_sys_newfstat+0x8b/0x110 fs/stat.c:551 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fedbb99c767 RSP: 002b:00007fff68d31d58 EFLAGS: 00000206 ORIG_RAX: 0000000000000005 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fedbb99c767 RDX: 0000000000000000 RSI: 00007fff68d31d60 RDI: 0000000000000003 RBP: 00007fff68d32f4c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 00007fff68d32f60 R13: 00007fedbba344bb R14: 000000000008d6e9 R15: 00007fff68d32fa0 task:kthreadd state:R running task stack:26136 pid:2 tgid:2 ppid:0 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7284 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:7606 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa10 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_is_held_type+0xf5/0x140 kernel/locking/lockdep.c:6021 Code: ff ff ff ff 65 0f c1 15 f1 95 ba 08 83 fa 01 8b 44 24 04 75 2d 9c 5a 80 e6 02 75 47 41 f7 c5 00 02 00 00 74 01 fb 48 83 c4 08 <5b> 5d 41 5c 41 5d 41 5e 41 5f e9 4c 46 03 00 e9 47 46 03 00 31 c0 RSP: 0018:ffffc90000077788 EFLAGS: 00000286 RAX: 0000000000000001 RBX: ffffffff8edec5a0 RCX: 0000000000000001 RDX: 0000000000000046 RSI: ffffffff8e36912e RDI: ffffffff8c623a80 RBP: ffff88801eaccb00 R08: 0000000000000006 R09: 0000000000001000 R10: 0000000000000000 R11: 0000000000000001 R12: 00000000ffffffff R13: 0000000000000246 R14: ffff88801eacd6d8 R15: 0000000000000001 lookup_page_ext+0x6e/0x100 mm/page_ext.c:253 page_ext_iter_begin include/linux/page_ext.h:136 [inline] __update_page_owner_free_handle.isra.0+0xe6/0x4b0 mm/page_owner.c:302 __reset_page_owner+0x93/0x190 mm/page_owner.c:339 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5010 copy_signal kernel/fork.c:1747 [inline] copy_process+0x3075/0x8380 kernel/fork.c:2308 kernel_clone+0x176/0x9d0 kernel/fork.c:2771 kernel_thread+0xdb/0x120 kernel/fork.c:2832 create_kthread kernel/kthread.c:459 [inline] kthreadd+0x498/0x7a0 kernel/kthread.c:817 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 1161 jiffies! g64309 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27560 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7376 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x8f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x17a/0x220 kernel/rcu/tree.c:2330 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 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: CPU: 0 UID: 0 PID: 3224 Comm: kworker/R-bat_e Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:stack_access_ok+0x1d/0x1d0 arch/x86/kernel/unwind_orc.c:405 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 48 b8 00 00 00 00 00 fc ff df 41 55 41 54 49 89 d4 48 89 fa 55 48 c1 ea 03 48 89 f5 53 <48> 89 fb 48 83 ec 08 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 3f 01 00 RSP: 0018:ffffc900000070d8 EFLAGS: 00000a06 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff91e9ab10 RDX: 1ffff92000000e2e RSI: ffffc9000de17e30 RDI: ffffc90000007170 RBP: ffffc9000de17e30 R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 000000000000d10c R12: 0000000000000008 R13: ffffc90000007170 R14: ffffc9000de17e60 R15: ffffc900000071a4 FS: 0000000000000000(0000) GS:ffff888123b4e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdcd310f00 CR3: 000000000eb96000 CR4: 00000000003526f0 Call Trace: deref_stack_reg arch/x86/kernel/unwind_orc.c:419 [inline] unwind_next_frame+0x1551/0x2090 arch/x86/kernel/unwind_orc.c:677 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6509 [inline] kfree+0x22b/0x6d0 mm/slub.c:6802 skb_kfree_head net/core/skbuff.c:1083 [inline] skb_free_head+0xb9/0x160 net/core/skbuff.c:1095 skb_release_data+0x659/0x860 net/core/skbuff.c:1122 skb_release_all net/core/skbuff.c:1197 [inline] __kfree_skb net/core/skbuff.c:1211 [inline] consume_skb net/core/skbuff.c:1448 [inline] consume_skb+0xc4/0x110 net/core/skbuff.c:1442 nft_synproxy_eval_v6 net/netfilter/nft_synproxy.c:91 [inline] nft_synproxy_do_eval+0x967/0xd30 net/netfilter/nft_synproxy.c:146 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x2e5/0x19d0 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0xf3/0x400 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xbf/0x220 net/netfilter/core.c:619 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:280 NF_HOOK include/linux/netfilter.h:323 [inline] ip6_input+0xe0/0x2f0 net/ipv6/ip6_input.c:545 dst_input include/net/dst.h:481 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:119 [inline] NF_HOOK include/linux/netfilter.h:325 [inline] NF_HOOK include/linux/netfilter.h:319 [inline] ipv6_rcv+0x263/0x3d0 net/ipv6/ip6_input.c:351 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6297 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6410 process_backlog+0x487/0x1600 net/core/dev.c:6761 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7830 napi_poll net/core/dev.c:7893 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:8050 handle_softirqs+0x1e6/0x9d0 kernel/softirq.c:645 do_softirq kernel/softirq.c:546 [inline] do_softirq+0xaf/0xf0 kernel/softirq.c:533 __local_bh_enable_ip+0xff/0x120 kernel/softirq.c:473 spin_unlock_bh include/linux/spinlock.h:407 [inline] batadv_tt_local_purge+0x21c/0x3d0 net/batman-adv/translation-table.c:1402 batadv_tt_purge+0x8b/0xbd0 net/batman-adv/translation-table.c:3753 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] rescuer_thread+0x918/0x14e0 kernel/workqueue.c:3703 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245