rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=64677, q=11785 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 9096 (4294998615-4294989519), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 9097 jiffies! g64677 f0x2 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:27048 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: CPU: 0 PID: 12290 Comm: syz.8.1777 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline] RIP: 0010:__local_bh_enable_ip+0x136/0x1c0 kernel/softirq.c:413 Code: 8a e8 3e fa 15 09 65 66 8b 05 86 22 b2 7e 66 85 c0 75 54 bf 01 00 00 00 e8 67 db 09 00 e8 62 60 3a 00 fb 65 8b 05 52 22 b2 7e <85> c0 75 05 e8 31 08 af ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00 RSP: 0018:ffffc900000065c0 EFLAGS: 00000282 RAX: 0000000000000102 RBX: 0000000000000200 RCX: 5b2b0147d7409200 RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80 RBP: ffffc90000006650 R08: ffffffff8e4a212f R09: 1ffffffff1c94425 R10: dffffc0000000000 R11: fffffbfff1c94426 R12: ffffffff88630b05 R13: 1ffff1100c9bfc1e R14: dffffc0000000000 R15: 1ffff92000000cb8 FS: 00007f45835186c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000140 CR3: 0000000023b3d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300 DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:856 [inline] __dev_queue_xmit+0x1449/0x35a0 net/core/dev.c:4452 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 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver+0xb5/0x150 net/bridge/br_forward.c:191 br_flood+0x31b/0x680 net/bridge/br_forward.c:237 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:__sanitizer_cov_trace_pc+0x49/0x60 kernel/kcov.c:222 Code: 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 <8b> 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 c3 0f 1f RSP: 0018:ffffc90003a46690 EFLAGS: 00000246 RAX: ffffffff813acf79 RBX: ffffffff8f6cac4b RCX: ffff888059bf5a00 RDX: ffffc9000d48c000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: dffffc0000000000 R08: ffff888059bf5a00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000002 R12: ffffc90003a467c8 R13: dffffc0000000000 R14: ffffffff8f6cac4a R15: ffffc90003a467c8 deref_stack_reg+0x29/0x240 arch/x86/kernel/unwind_orc.c:402 unwind_next_frame+0x1789/0x2970 arch/x86/kernel/unwind_orc.c:648 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492 __call_rcu_common kernel/rcu/tree.c:2721 [inline] call_rcu+0x158/0x930 kernel/rcu/tree.c:2837 context_switch kernel/sched/core.c:5383 [inline] __schedule+0x14da/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:kasan_quarantine_put+0x88/0x220 mm/kasan/quarantine.c:243 Code: e8 ed e9 ae ff 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 0f 85 83 00 00 00 41 f7 c7 00 02 00 00 74 01 fb 31 c0 <48> 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f c3 48 8d 80 c0 7a 03 00 45 RSP: 0018:ffffc90003a47018 EFLAGS: 00000206 RAX: 5b2b0147d7409201 RBX: ffff88807c47f000 RCX: 5b2b0147d7409200 RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80 RBP: ffff88807c47f000 R08: ffffffff8e4a212f R09: 1ffffffff1c94425 R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000 R13: ffffc90003a470b0 R14: 00000000000cbdb8 R15: 0000000000000286 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843 free_func_state kernel/bpf/verifier.c:1720 [inline] free_verifier_state+0xd8/0x230 kernel/bpf/verifier.c:1736 pop_stack kernel/bpf/verifier.c:2035 [inline] do_check+0xa459/0xdbe0 kernel/bpf/verifier.c:17349 do_check_common+0xadb/0x13e0 kernel/bpf/verifier.c:19706 do_check_main kernel/bpf/verifier.c:19769 [inline] bpf_check+0x649f/0xe970 kernel/bpf/verifier.c:20437 bpf_prog_load+0x11cb/0x16d0 kernel/bpf/syscall.c:2750 __sys_bpf+0x55a/0x800 kernel/bpf/syscall.c:5473 __do_sys_bpf kernel/bpf/syscall.c:5577 [inline] __se_sys_bpf kernel/bpf/syscall.c:5575 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5575 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: 0033:0x7f458258f749 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:00007f4583518038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f45827e5fa0 RCX: 00007f458258f749 RDX: 0000000000000048 RSI: 00002000000054c0 RDI: 0000000000000005 RBP: 00007f4582613f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f45827e6038 R14: 00007f45827e5fa0 R15: 00007fff78e9fe08