rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (9866 ticks this GP) idle=f3a/1/0x4000000000000000 softirq=38540/38540 fqs=56 (t=10502 jiffies g=58429 q=983) rcu: rcu_preempt kthread starved for 10035 jiffies! g58429 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:28880 pid: 11 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3779 [inline] __schedule+0x893/0x2130 kernel/sched/core.c:4528 schedule+0xcf/0x270 kernel/sched/core.c:4606 schedule_timeout+0x148/0x250 kernel/time/timer.c:1871 rcu_gp_fqs_loop kernel/rcu/tree.c:1925 [inline] rcu_gp_kthread+0xb4c/0x1c90 kernel/rcu/tree.c:2099 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 NMI backtrace for cpu 0 CPU: 0 PID: 20362 Comm: syz-executor.0 Not tainted 5.10.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 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+0x1e3/0x21e kernel/rcu/tree_stall.h:331 print_cpu_stall kernel/rcu/tree_stall.h:563 [inline] check_cpu_stall kernel/rcu/tree_stall.h:637 [inline] rcu_pending kernel/rcu/tree.c:3694 [inline] rcu_sched_clock_irq.cold+0x472/0xee8 kernel/rcu/tree.c:2567 update_process_times+0x77/0xd0 kernel/time/timer.c:1709 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1519 [inline] __hrtimer_run_queues+0x1ce/0xea0 kernel/time/hrtimer.c:1583 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1645 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1097 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:91 [inline] sysvec_apic_timer_interrupt+0x48/0x100 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:202 [inline] RIP: 0010:arch_atomic_fetch_add_unless include/linux/atomic-arch-fallback.h:1093 [inline] RIP: 0010:arch_atomic_add_unless include/linux/atomic-arch-fallback.h:1113 [inline] RIP: 0010:arch_atomic_inc_not_zero include/linux/atomic-arch-fallback.h:1129 [inline] RIP: 0010:atomic_inc_not_zero include/asm-generic/atomic-instrumented.h:799 [inline] RIP: 0010:dst_hold include/net/dst.h:227 [inline] RIP: 0010:sctp_packet_config+0x6d7/0xd60 net/sctp/output.c:133 Code: 40 e8 5d 2e 4f f9 31 ff 44 89 ee e8 a3 26 4f f9 45 85 ed 0f 84 0b 05 00 00 e8 45 2e 4f f9 41 8d 55 01 44 89 e8 f0 41 0f b1 17 <0f> 94 c2 31 ff 41 89 c5 89 d6 88 54 24 08 e8 36 26 4f f9 0f b6 54 RSP: 0018:ffffc900000076f0 EFLAGS: 00000246 RAX: 0000000000000009 RBX: ffff88801b80aab0 RCX: ffffffff8820d61d RDX: 000000000000000a RSI: ffffffff8820d62b RDI: 0000000000000005 RBP: ffff88801b80a800 R08: 0000000000000001 R09: ffff88805d32c143 R10: 0000000000000000 R11: 0000000000000001 R12: ffff888025d88000 R13: 0000000000000009 R14: ffff888014524c80 R15: ffff88805d32c140 sctp_outq_select_transport+0x1e4/0x740 net/sctp/outqueue.c:859 sctp_outq_flush_ctrl.constprop.0+0x291/0xc40 net/sctp/outqueue.c:893 sctp_outq_flush+0xf3/0x2580 net/sctp/outqueue.c:1186 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1801 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1185 [inline] sctp_do_sm+0x745/0x5120 net/sctp/sm_sideeffect.c:1156 sctp_generate_heartbeat_event+0x2b5/0x490 net/sctp/sm_sideeffect.c:391 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1410 expire_timers kernel/time/timer.c:1455 [inline] __run_timers.part.0+0x67c/0xa50 kernel/time/timer.c:1747 __run_timers kernel/time/timer.c:1728 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1760 __do_softirq+0x2a0/0x9f6 kernel/softirq.c:298 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0xaa/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x132/0x200 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x4d/0x100 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631 RIP: 0010:compound_head include/linux/page-flags.h:185 [inline] RIP: 0010:PageAnon include/linux/page-flags.h:484 [inline] RIP: 0010:zap_pte_range mm/memory.c:1243 [inline] RIP: 0010:zap_pmd_range mm/memory.c:1357 [inline] RIP: 0010:zap_pud_range mm/memory.c:1386 [inline] RIP: 0010:zap_p4d_range mm/memory.c:1407 [inline] RIP: 0010:unmap_page_range+0xb99/0x2640 mm/memory.c:1428 Code: 00 48 8b 44 24 08 80 48 20 08 48 85 ed 0f 84 11 fe ff ff e8 d9 be ce ff 48 8d 45 08 48 89 44 24 18 48 c1 e8 03 42 80 3c 30 00 <0f> 85 96 17 00 00 48 8b 45 08 31 ff 49 89 ec 48 89 c3 48 89 84 24 RSP: 0018:ffffc90003307798 EFLAGS: 00000246 RAX: 1ffffd40002049a9 RBX: 0000000000000001 RCX: ffffc90003307a60 RDX: ffff888021d80000 RSI: ffffffff81a14597 RDI: ffffc90003307a78 RBP: ffffea0001024d40 R08: 0000000000000000 R09: ffff888021d80007 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90003307a80 R13: ffff88802283e9a8 R14: dffffc0000000000 R15: 0000000001136000 unmap_single_vma+0x198/0x300 mm/memory.c:1473 unmap_vmas+0x168/0x2e0 mm/memory.c:1505 exit_mmap+0x2b1/0x530 mm/mmap.c:3220 __mmput+0x122/0x470 kernel/fork.c:1079 mmput+0x53/0x60 kernel/fork.c:1100 exit_mm kernel/exit.c:486 [inline] do_exit+0xa72/0x29b0 kernel/exit.c:796 do_group_exit+0x125/0x310 kernel/exit.c:906 get_signal+0x42a/0x1f10 kernel/signal.c:2758 arch_do_signal+0x82/0x2390 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:161 [inline] exit_to_user_mode_prepare+0x100/0x1a0 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x38/0x260 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e0f9 Code: Unable to access opcode bytes at RIP 0x45e0cf. RSP: 002b:00007f0b7bd55c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: 0000000020ffc000 RBX: 0000000000000006 RCX: 000000000045e0f9 RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffc000 RBP: 000000000119bfd8 R08: 0000000000000006 R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000246 R12: 000000000119bf8c R13: 00007fffd51b747f R14: 00007f0b7bd569c0 R15: 000000000119bf8c