rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=ece/1/0x4000000000000000 softirq=39569/39570 fqs=38 (detected by 0, t=10502 jiffies, g=61685, q=427) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 18782 Comm: syz-executor.1 Not tainted 5.9.0-rc2-next-20200828-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0xde0/0x5640 kernel/locking/lockdep.c:4453 Code: 6c 24 68 e8 42 de 9d 06 85 c0 0f 85 00 05 00 00 45 31 ff 48 b8 00 00 00 00 00 fc ff df 48 8b 5c 24 28 48 c7 04 03 00 00 00 00 <48> 8b 84 24 e8 00 00 00 65 48 2b 04 25 28 00 00 00 0f 85 93 2a 00 RSP: 0018:ffffc90000da8a68 EFLAGS: 00000087 RAX: dffffc0000000000 RBX: 1ffff920001b515f RCX: ffffffff815a153b RDX: 1ffff11008ae5135 RSI: 0000000000000001 RDI: ffffffff8c0414d8 RBP: ffff888045728a50 R08: 0000000000000000 R09: ffffffff8c6a59e7 R10: fffffbfff18d4b3c R11: 0000000000000001 R12: ffffffff8c0414c0 R13: dffffc0000000000 R14: ffff8880457280c0 R15: 0000000000000001 FS: 00007fa7837ae700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8876b8bdb8 CR3: 00000000a759a000 CR4: 00000000001526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:5005 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:159 debug_object_activate+0x12e/0x3e0 lib/debugobjects.c:636 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:480 [inline] enqueue_hrtimer+0x27/0x3f0 kernel/time/hrtimer.c:969 __run_hrtimer kernel/time/hrtimer.c:1541 [inline] __hrtimer_run_queues+0xc1e/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 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] sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:lock_release+0x0/0x8e0 kernel/locking/lockdep.c:5013 Code: e8 f5 95 5a 00 4c 8b 4c 24 10 e9 29 fd ff ff 48 c7 c7 f8 a3 bc 8a e8 df 95 5a 00 e9 66 fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 <48> ba 00 00 00 00 00 fc ff df 41 57 41 56 41 55 49 89 f5 41 54 49 RSP: 0018:ffffc900094aedf8 EFLAGS: 00000246 RAX: 0000000000040000 RBX: 0000000000000001 RCX: ffffc9000b197000 RDX: 0000000000040000 RSI: ffffffff86f086f1 RDI: ffffffff89c67640 RBP: ffff8880936c11c8 R08: 0000000000000001 R09: ffff8880936c11cb R10: 0000000000000000 R11: 0000000000000001 R12: ffff8880936c1000 R13: ffffc900094aefd0 R14: ffff8880a19572a0 R15: ffff8880952e0000 rcu_lock_release include/linux/rcupdate.h:253 [inline] rcu_read_unlock include/linux/rcupdate.h:695 [inline] in6_dev_get+0x193/0x2b0 include/net/addrconf.h:363 ip6_rt_copy_init+0x488/0xdb0 net/ipv6/route.c:1141 ip6_rt_cache_alloc+0x20e/0x820 net/ipv6/route.c:1352 ip6_pol_route+0xc6f/0x1190 net/ipv6/route.c:2246 pol_lookup_func include/net/ip6_fib.h:583 [inline] fib6_rule_lookup+0x111/0x6f0 net/ipv6/fib6_rules.c:115 ip6_route_output_flags_noref+0x2c2/0x360 net/ipv6/route.c:2510 ip6_route_output_flags+0x8b/0x310 net/ipv6/route.c:2523 ip6_dst_lookup_tail+0x5b9/0x1700 net/ipv6/ip6_output.c:1053 ip6_dst_lookup_flow+0x8c/0x1d0 net/ipv6/ip6_output.c:1156 rawv6_sendmsg+0xc82/0x38f0 net/ipv6/raw.c:928 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:671 sock_no_sendpage+0xee/0x130 net/core/sock.c:2838 kernel_sendpage net/socket.c:3644 [inline] sock_sendpage+0xe5/0x140 net/socket.c:944 pipe_to_sendpage+0x2ad/0x380 fs/splice.c:448 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x3dc/0x830 fs/splice.c:626 splice_from_pipe fs/splice.c:661 [inline] generic_splice_sendpage+0xd4/0x140 fs/splice.c:834 do_splice_from fs/splice.c:846 [inline] direct_splice_actor+0x171/0x2f0 fs/splice.c:1016 splice_direct_to_actor+0x38c/0x980 fs/splice.c:971 do_splice_direct+0x1b3/0x280 fs/splice.c:1059 do_sendfile+0x55f/0xd40 fs/read_write.c:1540 __do_sys_sendfile64 fs/read_write.c:1601 [inline] __se_sys_sendfile64 fs/read_write.c:1587 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1587 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fa7837adc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000027980 RCX: 000000000045d5b9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003 RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000 R10: 00008000fffffffe R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffcba4c2d9f R14: 00007fa7837ae9c0 R15: 000000000118cf4c rcu: rcu_preempt kthread starved for 10424 jiffies! g61685 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:29080 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1923 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2097 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294