rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P30613/1:b..l rcu: (detected by 1, t=10503 jiffies, g=180221, q=599 ncpus=2) task:syz.1.7563 state:R running task stack:22696 pid:30613 ppid:28806 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6868 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6892 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __local_bh_enable_ip+0x14b/0x1c0 kernel/softirq.c:413 local_bh_enable include/linux/bottom_half.h:33 [inline] xdp_test_run_batch net/bpf/test_run.c:361 [inline] bpf_test_run_xdp_live+0x18ce/0x1b30 net/bpf/test_run.c:383 bpf_prog_test_run_xdp+0x7d8/0x1140 net/bpf/test_run.c:1326 bpf_prog_test_run+0x31f/0x390 kernel/bpf/syscall.c:4140 __sys_bpf+0x49d/0x890 kernel/bpf/syscall.c:5509 __do_sys_bpf kernel/bpf/syscall.c:5595 [inline] __se_sys_bpf kernel/bpf/syscall.c:5593 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5593 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f611b79e159 RSP: 002b:00007f611c624028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f611ba25fa0 RCX: 00007f611b79e159 RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a RBP: 00007f611b83506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f611ba26038 R14: 00007f611ba25fa0 R15: 00007fff6e182978 rcu: rcu_preempt kthread starved for 1224 jiffies! g180221 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:26504 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 30623 Comm: syz.0.7564 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:unwind_next_frame+0x165/0x2990 arch/x86/kernel/unwind_orc.c:494 Code: 89 44 24 38 42 0f b6 04 38 84 c0 4c 89 fb 4d 8d 75 48 48 89 54 24 08 0f 85 7a 21 00 00 44 0f b6 3a 48 8b 44 24 48 80 3c 18 00 <74> 08 4c 89 f7 e8 31 62 a4 00 4d 8b 36 49 83 f7 01 4c 89 f7 4c 89 RSP: 0018:ffffc90000006d38 EFLAGS: 00000246 RAX: 1ffff92000000dca RBX: dffffc0000000000 RCX: ffff888020c3bc00 RDX: ffffc90000006e3d RSI: 0000000000000002 RDI: 0000000000000001 RBP: ffffc90000006e58 R08: ffffc90000006ed0 R09: 0000000000000009 R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900000076c0 R13: ffffc90000006e08 R14: ffffc90000006e50 R15: 0000000000000000 FS: 00007fbbe1e366c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560bd2282a38 CR3: 00000000695ec000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: 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+0x6a/0x4d0 mm/slab.h:770 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+0x17e/0x2c0 mm/slub.c:3519 skb_clone+0x1eb/0x370 net/core/skbuff.c:1915 deliver_clone net/bridge/br_forward.c:125 [inline] br_flood+0x411/0x670 net/bridge/br_forward.c:246 br_handle_frame_finish+0xf2d/0x15c0 net/bridge/br_input.c:215 br_nf_hook_thresh+0x3cd/0x4a0 net/bridge/br_netfilter_hooks.c:1188 br_nf_pre_routing_finish_ipv6+0x9e5/0xd20 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:304 [inline] br_nf_pre_routing_ipv6+0x34d/0x6a0 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+0x1240/0x14d0 net/bridge/br_input.c:424 __netif_receive_skb_core+0xf94/0x3ac0 net/core/dev.c:5564 __netif_receive_skb_one_core net/core/dev.c:5668 [inline] __netif_receive_skb+0x74/0x290 net/core/dev.c:5784 process_backlog+0x380/0x710 net/core/dev.c:6112 __napi_poll+0xbb/0x460 net/core/dev.c:6674 napi_poll net/core/dev.c:6741 [inline] net_rx_action+0x65f/0xcc0 net/core/dev.c:6877 handle_softirqs+0x27d/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:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5760 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc900044b7380 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: a8f7eb9d47a3f500 RDX: 0000000000000000 RSI: ffffffff8acade60 RDI: ffffffff8b1d3ba0 RBP: ffffc900044b7498 R08: dffffc0000000000 R09: 1ffffffff223d6a0 R10: dffffc0000000000 R11: fffffbfff223d6a1 R12: 1ffff92000896e7c R13: ffffffff8d1320e0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] __pte_offset_map+0x48/0x280 mm/pgtable-generic.c:287 pte_offset_map_nolock+0x44/0x130 mm/pgtable-generic.c:314 copy_pte_range mm/memory.c:1034 [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+0xf9e/0x3700 mm/memory.c:1323 dup_mmap kernel/fork.c:769 [inline] dup_mm kernel/fork.c:1700 [inline] copy_mm+0x1751/0x1e30 kernel/fork.c:1749 copy_process+0x16c9/0x3da0 kernel/fork.c:2510 kernel_clone+0x24b/0x8a0 kernel/fork.c:2919 __do_sys_clone kernel/fork.c:3062 [inline] __se_sys_clone kernel/fork.c:3046 [inline] __x64_sys_clone+0x1b7/0x230 kernel/fork.c:3046 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fbbe0f9e159 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:00007fbbe1e35fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fbbe1226090 RCX: 00007fbbe0f9e159 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000011 RBP: 00007fbbe103506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007fbbe1226128 R14: 00007fbbe1226090 R15: 00007ffc5729aac8 net_ratelimit: 2532 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:9a:02:13:84:15:8b, 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:aa:aa:aa:aa:aa:0c, 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:9a:02:13:84:15:8b, 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 bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, 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:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) net_ratelimit: 12014 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:e8:2d:1a:64:dd, 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:9a:02:13:84:15:8b, 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:aa:aa:aa:aa:aa:0c, 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:9a:02:13:84:15:8b, 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 bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)