rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10805/1:b..l rcu: (detected by 0, t=10503 jiffies, g=59977, q=519 ncpus=2) task:syz.1.1104 state:R running task stack:27560 pid:10805 ppid:8468 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1523 [inline] zap_pmd_range mm/memory.c:1571 [inline] zap_pud_range mm/memory.c:1600 [inline] zap_p4d_range mm/memory.c:1621 [inline] unmap_page_range+0x236f/0x2fe0 mm/memory.c:1642 unmap_vmas+0x25e/0x3a0 mm/memory.c:1732 exit_mmap+0x200/0xb50 mm/mmap.c:3302 __mmput+0x118/0x3c0 kernel/fork.c:1355 exit_mm+0x1da/0x2c0 kernel/exit.c:569 do_exit+0x88e/0x23c0 kernel/exit.c:870 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024 get_signal+0x12fc/0x1400 kernel/signal.c:2902 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: rcu_preempt kthread starved for 1562 jiffies! g59977 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:27208 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10799 Comm: syz.2.1102 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__kasan_check_read+0xa/0x20 mm/kasan/shadow.c:31 Code: 48 c7 c7 85 9a 78 8c 4c 89 e6 eb 0a 48 c7 c7 25 13 61 8c 48 89 de e8 f5 2a 7f 08 31 ed eb d4 cc f3 0f 1e fa 89 f6 48 8b 0c 24 <31> d2 e9 df ea ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 RSP: 0018:ffffc900001ee598 EFLAGS: 00000002 RAX: 0000000000000008 RBX: ffff888023e63c00 RCX: ffffffff8167b5a4 RDX: 0000000000000008 RSI: 0000000000000008 RDI: ffffffff90d94508 RBP: 0000000000000009 R08: dffffc0000000000 R09: 1ffffffff21b28a1 R10: dffffc0000000000 R11: fffffbfff21b28a2 R12: 0000000000000200 R13: dffffc0000000000 R14: ffff888023e647f8 R15: 0000000000000050 FS: 00007f9d5a4096c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f19e5451763 CR3: 00000000268a8000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] hlock_class kernel/locking/lockdep.c:228 [inline] mark_lock+0x94/0x320 kernel/locking/lockdep.c:4656 mark_usage kernel/locking/lockdep.c:4599 [inline] __lock_acquire+0xd49/0x7c80 kernel/locking/lockdep.c:5091 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754 seqcount_lockdep_reader_access+0xca/0x1c0 include/linux/seqlock.h:102 timekeeping_get_delta kernel/time/timekeeping.c:254 [inline] timekeeping_get_ns kernel/time/timekeeping.c:388 [inline] ktime_get+0x7f/0x280 kernel/time/timekeeping.c:848 hrtimer_forward_now include/linux/hrtimer.h:509 [inline] perf_swevent_hrtimer+0x433/0x530 kernel/events/core.c:11193 __run_hrtimer kernel/time/hrtimer.c:1750 [inline] __hrtimer_run_queues+0x4df/0xc40 kernel/time/hrtimer.c:1814 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline] RIP: 0010:unwind_next_frame+0x1d0e/0x2970 arch/x86/kernel/unwind_orc.c:672 Code: 0f 85 81 01 00 00 e8 91 d0 4a 00 eb 0c e8 8a d0 4a 00 eb 05 e8 83 d0 4a 00 bf 01 00 00 00 e8 89 ae 20 00 65 8b 1d 7a f5 c8 7e <31> ff 89 de e8 19 d4 4a 00 85 db 0f 84 e6 02 00 00 e8 5c d0 4a 00 RSP: 0018:ffffc900001ef058 EFLAGS: 00000293 RAX: 0000000080000302 RBX: 0000000080000301 RCX: 0000000000000300 RDX: 0000000000000100 RSI: ffffc900001ef580 RDI: 00000000ffffffff RBP: ffffc900001ef580 R08: ffff888023e63c00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900001ef128 R13: dffffc0000000000 R14: ffffc900001ef5c0 R15: ffffc900001ef138 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915 dev_queue_xmit_nit+0x24d/0xbb0 net/core/dev.c:2340 xmit_one net/core/dev.c:3615 [inline] dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3635 __dev_queue_xmit+0x1a64/0x35a0 net/core/dev.c:4425 dev_queue_xmit include/linux/netdevice.h:3113 [inline] br_dev_queue_push_xmit+0x6a6/0x850 net/bridge/br_forward.c:53 NF_HOOK+0x613/0x6a0 include/linux/netfilter.h:304 br_nf_post_routing+0xb41/0xfb0 net/bridge/br_netfilter_hooks.c:977 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline] nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:259 [inline] NF_HOOK+0x213/0x3d0 include/linux/netfilter.h:302 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:-1 [inline] br_nf_forward_finish+0xa33/0xe50 net/bridge/br_netfilter_hooks.c:684 NF_HOOK+0x613/0x6a0 include/linux/netfilter.h:304 br_nf_forward_ip+0xcc1/0x1110 net/bridge/br_netfilter_hooks.c:754 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline] nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:259 [inline] NF_HOOK+0x213/0x3d0 include/linux/netfilter.h:302 __br_forward+0x41f/0x600 net/bridge/br_forward.c:115 br_handle_frame_finish+0x143d/0x1950 net/bridge/br_input.c:215 br_nf_hook_thresh+0x3b6/0x480 net/bridge/br_netfilter_hooks.c:1184 br_nf_pre_routing_finish_ipv6+0x9e3/0xd90 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:304 [inline] br_nf_pre_routing_ipv6+0x34d/0x680 net/bridge/br_netfilter_ipv6.c:184 nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline] nf_hook_bridge_pre net/bridge/br_input.c:277 [inline] br_handle_frame+0x957/0x14c0 net/bridge/br_input.c:424 __netif_receive_skb_core+0xf6b/0x3ac0 net/core/dev.c:5502 __netif_receive_skb_one_core net/core/dev.c:5606 [inline] __netif_receive_skb+0x74/0x290 net/core/dev.c:5722 process_backlog+0x380/0x6e0 net/core/dev.c:6050 __napi_poll+0xc0/0x460 net/core/dev.c:6612 napi_poll net/core/dev.c:6679 [inline] net_rx_action+0x5ea/0xbf0 net/core/dev.c:6815 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:unwind_next_frame+0x621/0x2970 arch/x86/kernel/unwind_orc.c:505 Code: 02 4b 8d 1c 64 48 01 db 48 01 c3 74 77 e8 77 e7 4a 00 4c 8b 24 24 4c 8d 73 04 4c 8d 7b 05 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 d0 1c 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc90004fcf6b8 EFLAGS: 00000a03 RAX: 0000000000000000 RBX: ffffffff8ed93748 RCX: 0000000000080000 RDX: ffffc9000dbd2000 RSI: 0000000000000ed1 RDI: 0000000000000ed2 RBP: ffffc90004fcf7d8 R08: ffffc90004fcf850 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000002 R12: ffffc90004fcf788 R13: dffffc0000000000 R14: ffffffff8ed9374c R15: ffffffff8ed9374d arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf7/0x1f0 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1154 [inline] free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429 __slab_free+0x35e/0x410 mm/slub.c:3736 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519 kmem_cache_zalloc include/linux/slab.h:711 [inline] lsm_file_alloc security/security.c:612 [inline] security_file_alloc+0x34/0x120 security/security.c:2603 init_file+0x94/0x1f0 fs/file_table.c:161 alloc_empty_file+0xb7/0x1d0 fs/file_table.c:210 alloc_file+0x5c/0x600 fs/file_table.c:293 alloc_file_pseudo+0x17e/0x200 fs/file_table.c:336 sock_alloc_file+0xb7/0x280 net/socket.c:469 sock_map_fd net/socket.c:494 [inline] __sys_socket+0x13d/0x1a0 net/socket.c:1724 __do_sys_socket net/socket.c:1729 [inline] __se_sys_socket net/socket.c:1727 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1727 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9d5958f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9d5a409038 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 00007f9d597e6270 RCX: 00007f9d5958f749 RDX: 000000000000003a RSI: 0000000000000002 RDI: 000000000000000a RBP: 00007f9d59613f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9d597e6308 R14: 00007f9d597e6270 R15: 00007ffeb6c72618 net_ratelimit: 143 callbacks suppressed bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:20, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:20, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:20, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:20, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:20, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) net_ratelimit: 3 callbacks suppressed bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:20, vlan:0) bridge0: received packet on team0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)