rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5888/1:b..l rcu: (detected by 0, t=10502 jiffies, g=9425, q=926 ncpus=2) task:syz.2.14 state:R running task stack:24840 pid:5888 ppid:5773 flags:0x00004006 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:5512 __do_sys_bpf kernel/bpf/syscall.c:5598 [inline] __se_sys_bpf kernel/bpf/syscall.c:5596 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5596 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: 0033:0x7fc73e79e2d9 RSP: 002b:00007fc73f717028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fc73ea26090 RCX: 00007fc73e79e2d9 RDX: 0000000000000048 RSI: 0000200000000580 RDI: 000000000000000a RBP: 00007fc73e835888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc73ea26128 R14: 00007fc73ea26090 R15: 00007ffce24302a8 rcu: rcu_preempt kthread starved for 9290 jiffies! g9425 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:26216 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: CPU: 0 PID: 5892 Comm: syz.1.15 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:seqcount_lockdep_reader_access+0x19a/0x1d0 include/linux/seqlock.h:105 Code: 00 4d 85 e4 75 16 e8 95 cb 0f 00 eb 15 e8 8e cb 0f 00 e8 e9 45 1b 09 4d 85 e4 74 ea e8 7f cb 0f 00 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 43 c7 44 3e 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc900000063a0 EFLAGS: 00000246 RAX: ffffffff8177c531 RBX: 0000000000000000 RCX: ffff88802ad80000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000006458 R08: ffffffff91ff152f R09: 1ffffffff23fe2a5 R10: dffffc0000000000 R11: fffffbfff23fe2a6 R12: 0000000000000200 R13: 1ffff92000000c9c R14: 1ffff92000000c74 R15: dffffc0000000000 FS: 00007f483a8e86c0(0000) GS:ffff8880b8c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3234bf34b8 CR3: 000000005c981000 CR4: 00000000003506f0 Call Trace: ktime_get_with_offset+0x94/0x330 kernel/time/timekeeping.c:889 ktime_get_real include/linux/timekeeping.h:79 [inline] netif_rx_internal+0x33d/0x4e0 net/core/dev.c:5177 __netif_rx+0x78/0xc0 net/core/dev.c:5220 veth_forward_skb drivers/net/veth.c:325 [inline] veth_xmit+0x57a/0xa30 drivers/net/veth.c:378 __netdev_start_xmit include/linux/netdevice.h:4998 [inline] netdev_start_xmit include/linux/netdevice.h:5012 [inline] xmit_one net/core/dev.c:3649 [inline] dev_hard_start_xmit+0x269/0x790 net/core/dev.c:3665 __dev_queue_xmit+0x1be8/0x37e0 net/core/dev.c:4478 dev_queue_xmit include/linux/netdevice.h:3170 [inline] br_dev_queue_push_xmit+0x6b7/0x880 net/bridge/br_forward.c:53 NF_HOOK+0x66e/0x700 include/linux/netfilter.h:304 br_nf_post_routing+0xa3b/0xec0 net/bridge/br_netfilter_hooks.c:981 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_finish+0xd3/0x130 net/bridge/br_forward.c:66 br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:1188 [inline] br_nf_forward_finish+0xa69/0xe90 net/bridge/br_netfilter_hooks.c:688 NF_HOOK+0x66e/0x700 include/linux/netfilter.h:304 br_nf_forward_ip+0xc78/0x10d0 net/bridge/br_netfilter_hooks.c:758 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+0x317/0x670 net/bridge/br_forward.c:237 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:qlist_free_all+0x26/0xd0 mm/kasan/quarantine.c:-1 Code: 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 48 8b 2f 48 85 ed 0f 84 af 00 00 00 49 89 f6 48 89 fb 49 bd 00 00 00 00 00 fc ff df <49> 89 ef 4d 89 f4 4d 85 f6 75 0b 4c 89 ff e8 c7 04 00 00 49 89 c4 RSP: 0018:ffffc90004b3fbb0 EFLAGS: 00000286 RAX: 688f2e4f2661a500 RBX: ffffc90004b3fbe8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff RBP: ffff88802bab6300 R08: ffff8880b8c42103 R09: 1ffff11017188420 R10: dffffc0000000000 R11: ffffed1017188421 R12: ffff888018842140 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802f848000 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 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_lru+0x175/0x2b0 mm/slub.c:3526 __d_alloc+0x31/0x710 fs/dcache.c:1773 d_alloc_pseudo+0x1d/0x70 fs/dcache.c:1905 alloc_file_pseudo+0xe4/0x210 fs/file_table.c:363 sock_alloc_file+0xb7/0x280 net/socket.c:469 __sys_socketpair+0x376/0x550 net/socket.c:1809 __do_sys_socketpair net/socket.c:1831 [inline] __se_sys_socketpair net/socket.c:1828 [inline] __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1828 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: 0033:0x7f483999e2d9 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:00007f483a8e8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035 RAX: ffffffffffffffda RBX: 00007f4839c25fa0 RCX: 00007f483999e2d9 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001 RBP: 00007f4839a35888 R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000640 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4839c26038 R14: 00007f4839c25fa0 R15: 00007ffebc342618