rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7333/1:b..l rcu: (detected by 0, t=10502 jiffies, g=16821, q=420 ncpus=2) task:syz.2.462 state:R running task stack:27816 pid:7333 ppid:7327 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 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+0x2315/0x3000 mm/memory.c:1642 unmap_vmas+0x286/0x3f0 mm/memory.c:1732 exit_mmap+0x238/0xb90 mm/mmap.c:3302 __mmput+0x118/0x3c0 kernel/fork.c:1356 exit_mm+0x1f2/0x2c0 kernel/exit.c:569 do_exit+0x8dd/0x2460 kernel/exit.c:870 __do_sys_exit kernel/exit.c:991 [inline] __se_sys_exit kernel/exit.c:989 [inline] __x64_sys_exit+0x40/0x40 kernel/exit.c:989 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4d0e79cdd9 RSP: 002b:00007f4d0f732fd8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c RAX: ffffffffffffffda RBX: 00007f4d0ea15fa0 RCX: 00007f4d0e79cdd9 RDX: 00007f4d0f7339c8 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f4d0e832d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4d0ea16038 R14: 00007f4d0ea15fa0 R15: 00007fff43160848 rcu: rcu_preempt kthread starved for 9601 jiffies! g16821 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:27720 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 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: 7325 Comm: syz.1.469 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:asm_sysvec_apic_timer_interrupt+0x0/0x20 arch/x86/include/asm/idtentry.h:687 Code: 86 50 e6 ff e9 c1 04 00 00 90 f3 0f 1e fa 0f 01 ca fc 6a ff e8 c1 03 00 00 48 89 c4 48 89 e7 e8 a6 4f e6 ff e9 a1 04 00 00 90 0f 1e fa 0f 01 ca fc 6a ff e8 a1 03 00 00 48 89 c4 48 89 e7 e8 RSP: 0018:ffffc900001ef9a8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffffc900001efae0 RCX: ffff888077a70000 RDX: 0000000000000100 RSI: 0000000000000002 RDI: 0000000000000002 RBP: 0000000000000002 R08: ffff888077a70000 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900001efaa8 R13: dffffc0000000000 R14: 0000000000000002 R15: ffffffff8f11e686 FS: 00007f4bb32976c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3337186e80 CR3: 0000000024ad2000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: RIP: 0010:unwind_next_frame+0x1c42/0x2970 arch/x86/kernel/unwind_orc.c:664 Code: 89 37 48 8b 44 24 18 42 0f b6 04 28 84 c0 48 8b 5c 24 60 0f 85 a3 0a 00 00 41 8b 2c 24 89 ef 44 8b b4 24 8c 00 00 00 44 89 f6 79 cf 4b 00 44 39 f5 0f 85 a1 00 00 00 48 8b 44 24 68 42 80 3c RSP: 0018:ffffc900001ef9d8 EFLAGS: 00000246 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 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+0x11a/0x2d0 mm/slub.c:3519 skb_ext_maybe_cow net/core/skbuff.c:6661 [inline] skb_ext_add+0x1b3/0x8e0 net/core/skbuff.c:6735 nf_bridge_unshare net/bridge/br_netfilter_hooks.c:165 [inline] br_nf_forward_ip+0xc6/0x1110 net/bridge/br_netfilter_hooks.c:709 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+0x23e/0x3e0 include/linux/netfilter.h:302 __br_forward+0x433/0x610 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/0x670 net/bridge/br_forward.c:237 br_handle_frame_finish+0x13c5/0x18f0 net/bridge/br_input.c:215 br_nf_hook_thresh+0x3cd/0x4a0 net/bridge/br_netfilter_hooks.c:1184 br_nf_pre_routing_finish_ipv6+0x9dc/0xd00 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:304 [inline] br_nf_pre_routing_ipv6+0x349/0x6b0 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+0x1245/0x14d0 net/bridge/br_input.c:424 __netif_receive_skb_core+0xfab/0x3af0 net/core/dev.c:5540 __netif_receive_skb_one_core net/core/dev.c:5644 [inline] __netif_receive_skb+0x74/0x290 net/core/dev.c:5760 process_backlog+0x391/0x6f0 net/core/dev.c:6088 __napi_poll+0xc0/0x460 net/core/dev.c:6650 napi_poll net/core/dev.c:6717 [inline] net_rx_action+0x616/0xc40 net/core/dev.c:6853 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+0xd3/0x190 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:schedule_debug kernel/sched/core.c:5938 [inline] RIP: 0010:__schedule+0x13f/0x45a0 kernel/sched/core.c:6591 Code: 30 48 8d 58 20 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 70 f2 50 f7 48 8b 1b 48 89 d8 48 c1 e8 03 42 80 3c 30 00 <74> 08 48 89 df e8 57 f2 50 f7 48 81 3b 9d 6e ac 57 0f 85 7d 16 00 RSP: 0018:ffffc90004957180 EFLAGS: 00000246 RAX: 1ffff9200092a000 RBX: ffffc90004950000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90004957320 RBP: ffffc90004957390 R08: ffffc9000495731f R09: 0000000000000000 R10: ffffc90004957310 R11: fffff5200092ae64 R12: 1ffff9200092ae50 R13: ffff8880b8f00000 R14: dffffc0000000000 R15: 0000000000000001 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 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:__might_resched+0x4/0x630 kernel/sched/core.c:10166 Code: ff 49 89 fc 4c 89 f7 89 f5 e8 f8 0e 81 00 4c 89 e7 89 ee e9 60 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec e0 00 RSP: 0018:ffffc90004957518 EFLAGS: 00000246 RAX: 08128bc3e349ed00 RBX: ffffffff81c9646f RCX: 08128bc3e349ed00 RDX: 0000000000000000 RSI: 0000000000000454 RDI: ffffffff8ad4d5a0 RBP: ffffc90004957830 R08: ffffffff8e8b19af R09: 1ffffffff1d16335 R10: dffffc0000000000 R11: fffffbfff1d16336 R12: 00007f4bb1a1c000 R13: dffffc0000000000 R14: 00007f4bb1c00000 R15: 0000000000000000 copy_pte_range mm/memory.c:1108 [inline] copy_pmd_range mm/memory.c:1168 [inline] copy_pud_range mm/memory.c:1205 [inline] copy_p4d_range mm/memory.c:1229 [inline] copy_page_range+0x2c59/0x3670 mm/memory.c:1323 dup_mmap kernel/fork.c:768 [inline] dup_mm kernel/fork.c:1693 [inline] copy_mm+0x1281/0x1d80 kernel/fork.c:1742 copy_process+0x16f7/0x3d80 kernel/fork.c:2507 kernel_clone+0x24b/0x8a0 kernel/fork.c:2915 __do_sys_clone kernel/fork.c:3058 [inline] __se_sys_clone kernel/fork.c:3042 [inline] __x64_sys_clone+0x1b7/0x230 kernel/fork.c:3042 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4bb239cdd9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4bb3296fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f4bb2616090 RCX: 00007f4bb239cdd9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f4bb2432d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4bb2616128 R14: 00007f4bb2616090 R15: 00007ffe814da838 net_ratelimit: 1274 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) net_ratelimit: 13640 callbacks suppressed bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:22:69:b8:36:bb:a3, vlan:0)