rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (9333 ticks this GP) idle=435/1/0x4000000000000000 softirq=8359/8359 fqs=2 (t=10503 jiffies g=10181 q=825) rcu: rcu_preempt kthread starved for 10499 jiffies! g10181 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:28256 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4e90 kernel/sched/core.c:6296 schedule+0xd2/0x260 kernel/sched/core.c:6369 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1971 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2144 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 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: 3615 Comm: syz-fuzzer Not tainted 5.16.0-rc6-next-20211224-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:unwind_next_frame+0x3e0/0x1ce0 arch/x86/kernel/unwind_orc.c:456 Code: 00 00 00 00 00 fc ff df 4c 89 fa 48 c1 ea 03 0f b6 04 02 4c 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 bd 08 00 00 41 0f b6 40 04 0f 0f 85 aa 00 00 00 49 8d 78 05 48 b8 00 00 00 00 00 fc ff df RSP: 0018:ffffc9000282f6a8 EFLAGS: 00000046 RAX: 0000000000000015 RBX: 1ffff92000505edd RCX: ffffffff8148947e RDX: 0000000000000006 RSI: ffffffff8e0fa9da RDI: ffffffff8da07eb4 RBP: 0000000000000001 R08: ffffffff8e0fa9da R09: 0000000000000001 R10: fffff52000505efb R11: 0000000000088077 R12: ffffc9000282f7c8 R13: ffffc9000282f7b5 R14: ffffc9000282f780 R15: ffffffff8e0fa9de FS: 000000c00033fc90(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00002afa0 CR3: 0000000019c76000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x7d/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:45 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:236 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3509 [inline] kmem_cache_free+0xdb/0x3b0 mm/slub.c:3526 __sigqueue_free kernel/signal.c:458 [inline] __sigqueue_free kernel/signal.c:450 [inline] collect_signal+0x364/0x630 kernel/signal.c:597 __dequeue_signal kernel/signal.c:619 [inline] dequeue_signal+0x35f/0x650 kernel/signal.c:642 get_signal+0x767/0x28c0 kernel/signal.c:2748 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x46e460 Code: 0f 05 89 44 24 20 c3 cc cc cc 8b 7c 24 08 48 8b 74 24 10 8b 54 24 18 44 8b 54 24 1c 49 c7 c0 00 00 00 00 b8 19 01 00 00 0f 05 <89> 44 24 20 c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc RSP: 002b:000000c00003b7f0 EFLAGS: 00000246 ORIG_RAX: 0000000000000119 RAX: fffffffffffffffc RBX: 00000000000003c4 RCX: 000000000046e460 RDX: 0000000000000080 RSI: 000000c00003b840 RDI: 0000000000000003 RBP: 000000c00003be40 R08: 0000000000000000 R09: 00007ffcfffc0080 R10: 00000000000003c4 R11: 0000000000000246 R12: 000000c001766768 R13: 000000c001766778 R14: 0000000000000000 R15: 0000000000000000 NMI backtrace for cpu 0 CPU: 0 PID: 4274 Comm: syz-executor.0 Not tainted 5.16.0-rc6-next-20211224-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x262/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3920 [inline] rcu_sched_clock_irq.cold+0x5c/0x759 kernel/rcu/tree.c:2625 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:pie_calculate_probability+0x426/0x7c0 net/sched/sch_pie.c:419 Code: ff 44 89 e6 e8 2b 93 0a fa 45 84 e4 75 26 e8 41 8f 0a fa 48 8b 54 24 08 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 85 34 03 00 00 4c 89 73 08 48 83 c4 48 5b 5d 41 5c 41 5d 41 5e RSP: 0018:ffffc90000007c50 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff888052f99830 RCX: 0000000000000100 RDX: 1ffff1100a5f3307 RSI: ffffffff876d753f RDI: 0000000000000003 RBP: ffff888052f99868 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff876d7535 R11: 0000000000000000 R12: 0000000000000000 R13: ffff88807dde3b00 R14: 0000000000000000 R15: 0000000000000000 fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__local_bh_enable_ip+0xa8/0x120 kernel/softirq.c:390 Code: 1d 4d a0 bb 7e 65 8b 05 46 a0 bb 7e a9 00 ff ff 00 74 45 bf 01 00 00 00 e8 95 41 09 00 e8 00 7d 37 00 fb 65 8b 05 28 a0 bb 7e <85> c0 74 58 5b 5d c3 65 8b 05 76 a7 bb 7e 85 c0 75 a2 0f 0b eb 9e RSP: 0018:ffffc9000b18f838 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 00000000fffffe00 RCX: 1ffffffff2003a3e RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffffff87bde936 R08: 0000000000000001 R09: ffffffff8ffb5a57 R10: 0000000000000001 R11: 0000000000000001 R12: 00000000ffffffe0 R13: 0000000000000000 R14: ffffc9000b18f930 R15: 0000000000000000 tcp_sendmsg+0x36/0x40 net/ipv4/tcp.c:1441 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:641 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:725 io_send+0x1bd/0x450 fs/io_uring.c:5028 io_issue_sqe+0x2432/0x74d0 fs/io_uring.c:6837 __io_queue_sqe fs/io_uring.c:7164 [inline] io_queue_sqe fs/io_uring.c:7206 [inline] io_submit_sqe fs/io_uring.c:7414 [inline] io_submit_sqes+0x11df/0x91b0 fs/io_uring.c:7520 __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10222 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f1a0bb82e99 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1a0a4f8168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007f1a0bc95f60 RCX: 00007f1a0bb82e99 RDX: 0000000000000000 RSI: 00000000000061bd RDI: 0000000000000003 RBP: 00007f1a0bbdcff1 R08: 0000000000000000 R09: fffffffffffffdae R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff42ecba8f R14: 00007f1a0a4f8300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 7 bytes skipped: 0: df 4c 89 fa fisttps -0x6(%rcx,%rcx,4) 4: 48 c1 ea 03 shr $0x3,%rdx 8: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax c: 4c 89 fa mov %r15,%rdx f: 83 e2 07 and $0x7,%edx 12: 38 d0 cmp %dl,%al 14: 7f 08 jg 0x1e 16: 84 c0 test %al,%al 18: 0f 85 bd 08 00 00 jne 0x8db 1e: 41 0f b6 40 04 movzbl 0x4(%r8),%eax * 23: a8 0f test $0xf,%al <-- trapping instruction 25: 0f 85 aa 00 00 00 jne 0xd5 2b: 49 8d 78 05 lea 0x5(%r8),%rdi 2f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 36: fc ff df