rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8027 rcu: (detected by 0, t=10502 jiffies, g=25025, q=610 ncpus=2) task:syz.2.599 state:R running task stack:24968 pid:8027 ppid:5769 flags:0x0000400e Call Trace: sched_show_task+0x49b/0x5c0 kernel/sched/core.c:9179 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline] print_other_cpu_stall+0xff9/0x1380 kernel/rcu/tree_stall.h:637 check_cpu_stall kernel/rcu/tree_stall.h:809 [inline] rcu_pending kernel/rcu/tree.c:3950 [inline] rcu_sched_clock_irq+0x88e/0x1230 kernel/rcu/tree.c:2295 update_process_times+0x147/0x1b0 kernel/time/timer.c:2072 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492 __run_hrtimer kernel/time/hrtimer.c:1750 [inline] __hrtimer_run_queues+0x4e1/0xc40 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:get_random_u8+0x51b/0x970 drivers/char/random.c:520 Code: fc 4d 85 f6 75 16 e8 44 c7 db fc eb 15 e8 3d c7 db fc e8 58 ac da 05 4d 85 f6 74 ea e8 2e c7 db fc fb 0f b6 84 24 00 01 00 00 <43> c6 44 2f 18 f8 48 c7 44 24 40 0e 36 e0 45 4b c7 04 2f 00 00 00 RSP: 0018:ffffc90000006f60 EFLAGS: 00000246 RAX: 00000000000000cf RBX: 0000000000000000 RCX: ffff888023b49e00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900000070d0 R08: ffffffff911c35ff R09: 1ffffffff22386bf R10: dffffc0000000000 R11: fffffbfff22386c0 R12: 0000000000000001 R13: dffffc0000000000 R14: 0000000000000200 R15: 1ffff92000000df4 get_random_u32_below include/linux/random.h:78 [inline] kfence_guarded_alloc+0xa2/0xe30 mm/kfence/core.c:400 __kfence_alloc+0x39a/0x3d0 mm/kfence/core.c:1150 kfence_alloc include/linux/kfence.h:129 [inline] slab_alloc_node mm/slub.c:3481 [inline] __kmem_cache_alloc_node+0x1f7/0x250 mm/slub.c:3534 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] ref_tracker_alloc+0x162/0x4c0 lib/ref_tracker.c:203 __netdev_tracker_alloc include/linux/netdevice.h:4110 [inline] netdev_hold include/linux/netdevice.h:4139 [inline] ___neigh_create+0xc8b/0x2440 net/core/neighbour.c:658 ip6_finish_output2+0x1581/0x1630 net/ipv6/ip6_output.c:132 dst_output include/net/dst.h:467 [inline] NF_HOOK include/linux/netfilter.h:304 [inline] ndisc_send_skb+0xc26/0x14f0 net/ipv6/ndisc.c:513 addrconf_rs_timer+0x2d5/0x630 net/ipv6/addrconf.c:4024 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x542/0x800 kernel/time/timer.c:2023 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036 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:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255 Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 90 43 32 09 e8 eb 27 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc90010417118 EFLAGS: 00000286 RAX: e611b184c84b4100 RBX: 0000000000000000 RCX: e611b184c84b4100 RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c89a0 RBP: ffffc90010417170 R08: ffffffff911c3537 R09: 1ffffffff22386a6 R10: dffffc0000000000 R11: fffffbfff22386a7 R12: ffff888023b49e00 R13: dffffc0000000000 R14: ffff88802e510000 R15: ffff8880b8e3cac8 context_switch kernel/sched/core.c:5384 [inline] __schedule+0x155b/0x45a0 kernel/sched/core.c:6700 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:debug_lockdep_rcu_enabled+0x0/0x30 kernel/rcu/update.c:318 Code: 2c 05 04 00 75 e8 48 c7 c7 80 c8 ca 8a 48 c7 c6 a0 ec ca 8a e8 21 cd ca f6 0f 0b eb d1 cc cc cc cc cc cc cc cc cc cc cc cc cc 0f 1e fa 31 c0 83 3d 8f f8 04 04 00 74 1d 83 3d 16 2c 05 04 00 RSP: 0018:ffffc90010417518 EFLAGS: 00000287 RAX: ffffffff81ca5d2c RBX: 1ffff92002082ea8 RCX: 0000000000080000 RDX: ffffc9000d11a000 RSI: 0000000000014670 RDI: 0000000000014671 RBP: ffffc900104175f0 R08: ffffffff911c3537 R09: 1ffffffff22386a6 R10: dffffc0000000000 R11: fffffbfff22386a7 R12: 0000000000000200 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffffff81ca5ade rcu_read_unlock include/linux/rcupdate.h:815 [inline] count_memcg_event_mm+0x2e2/0x3c0 include/linux/memcontrol.h:1104 mm_account_fault mm/memory.c:5222 [inline] handle_mm_fault+0x2b25/0x4c00 mm/memory.c:5369 do_user_addr_fault+0x730/0x12c0 arch/x86/mm/fault.c:1371 handle_page_fault arch/x86/mm/fault.c:1463 [inline] exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:71 Code: 75 f1 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 a4 c3 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48 29 f8 48 01 RSP: 0018:ffffc90010417978 EFLAGS: 00050206 RAX: ffffffff8427d801 RBX: 0000000000001000 RCX: 0000000000000100 RDX: 0000000000000001 RSI: 0000200000008000 RDI: ffff88802dbaff00 RBP: ffffc90010417ad8 R08: ffff88802dbaffff R09: 1ffff11005b75fff R10: dffffc0000000000 R11: ffffed1005b76000 R12: ffff88802dbaf000 R13: 0000200000007100 R14: ffffc90010417db8 R15: 1ffff92002082fb7 copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:127 [inline] copyin lib/iov_iter.c:193 [inline] _copy_from_iter+0x24e/0x12e0 lib/iov_iter.c:390 copy_page_from_iter+0x7b/0x100 lib/iov_iter.c:542 pipe_write+0x868/0x1b10 fs/pipe.c:538 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x46c/0x990 fs/read_write.c:584 ksys_write+0x150/0x260 fs/read_write.c:637 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: 0033:0x7f4cbd59c819 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:00007f4cbe446028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f4cbd815fa0 RCX: 00007f4cbd59c819 RDX: 000000000000cfa4 RSI: 0000200000000100 RDI: 0000000000000000 RBP: 00007f4cbd632c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4cbd816038 R14: 00007f4cbd815fa0 R15: 00007ffcc4bd6ff8