rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=0d2/1/0x4000000000000000 softirq=150274/150274 fqs=9 (t=10501 jiffies g=271809 q=193) NMI backtrace for cpu 0 CPU: 0 PID: 17786 Comm: syz-executor.0 Not tainted 5.9.0-rc1-next-20200821-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:165 [inline] rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:318 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline] check_cpu_stall kernel/rcu/tree_stall.h:625 [inline] rcu_pending kernel/rcu/tree.c:3694 [inline] rcu_sched_clock_irq.cold+0x5b3/0xcc3 kernel/rcu/tree.c:2565 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 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:1524 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0x4c/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:196 Code: 48 89 ef 5d e9 41 9a 3f 00 5d be 03 00 00 00 e9 d6 19 28 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 <65> 48 8b 14 25 c0 fe 01 00 65 8b 05 b0 8b 8d 7e a9 00 01 ff 00 48 RSP: 0018:ffffc90000007cc8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff8399ceac RDX: 0000000000000001 RSI: ffff888035074300 RDI: 0000000000000001 RBP: 0000000000000014 R08: 0000000000000000 R09: ffffffff8abb5e8f R10: 0000000000000000 R11: 0000000000000001 R12: 00000000246dee61 R13: 0000000000000000 R14: 1ffff92000000fa7 R15: ffff8880ae625580 __preempt_count_add arch/x86/include/asm/preempt.h:79 [inline] rcu_read_lock_sched_notrace include/linux/rcupdate.h:757 [inline] trace_prandom_u32 include/trace/events/random.h:310 [inline] prandom_u32+0x235/0x380 lib/random32.c:86 garp_join_timer_arm+0x21/0x80 net/802/garp.c:397 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x2de/0xa24 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x9d/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+0x1f3/0x230 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:321 [inline] RIP: 0010:rcu_is_watching+0x5d/0xb0 kernel/rcu/tree.c:1100 Code: 80 3c 11 00 75 61 48 03 1c c5 00 49 84 89 48 b8 00 00 00 00 00 fc ff df 48 8d bb 28 01 00 00 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 25 8b 83 28 01 00 RSP: 0018:ffffc90011d0f760 EFLAGS: 00000a02 RAX: dffffc0000000000 RBX: ffff8880ae636bc0 RCX: 1ffffffff1308920 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff8880ae636ce8 RBP: ffffea000153ad00 R08: 0000000000000001 R09: ffffea000153ad33 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: ffffea000153ad08 rcu_read_unlock include/linux/rcupdate.h:691 [inline] __unlock_page_memcg mm/memcontrol.c:2139 [inline] unlock_page_memcg+0xbd/0x160 mm/memcontrol.c:2150 zap_pte_range mm/memory.c:1091 [inline] zap_pmd_range mm/memory.c:1195 [inline] zap_pud_range mm/memory.c:1224 [inline] zap_p4d_range mm/memory.c:1245 [inline] unmap_page_range+0xf6a/0x2ab0 mm/memory.c:1266 unmap_single_vma+0x198/0x300 mm/memory.c:1311 unmap_vmas+0x168/0x2e0 mm/memory.c:1343 exit_mmap+0x2b1/0x530 mm/mmap.c:3228 __mmput+0x122/0x470 kernel/fork.c:1075 mmput+0x53/0x60 kernel/fork.c:1096 exit_mm kernel/exit.c:483 [inline] do_exit+0xa8b/0x29f0 kernel/exit.c:793 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:135 [inline] exit_to_user_mode_prepare+0x15d/0x1c0 kernel/entry/common.c:166 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:241 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x417021 Code: Bad RIP value. RSP: 002b:00007f44754e7bb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: fffffffffffffffe RBX: 00007f44754e7bd0 RCX: 0000000000417021 RDX: 00007f44754e7be7 RSI: 0000000000000002 RDI: 00007f44754e7bd0 RBP: 000000000118cf78 R08: 0000000000000000 R09: 0000000000000017 R10: 000000000000000c R11: 0000000000000293 R12: 000000000118cf4c R13: 00007ffee4bfc7af R14: 00007f44754e89c0 R15: 000000000118cf4c