INFO: rcu_preempt self-detected stall on CPU
	1-...: (12500 ticks this GP) idle=4ab/140000000000001/0 softirq=16332/16332 fqs=0 
	 (t=12500 jiffies g=3178 c=3177 q=1088)
rcu_preempt kthread starved for 12500 jiffies! g3178 c3177 f0x0 s3 ->state=0x1
Task dump for CPU 1:
syz-executor2   R  running task    25872  7901   3935 0x0000000c
 0000000000000f5f f244470ae5c3041e ffff8801db307be8 ffffffff8140c4fc
 ffff8801db31f4c0 0000000000000001 dffffc0000000000 ffffffff844bef00
 ffffffff844bef84 ffff8801db307c08 ffffffff8140c787 ffffffff844bef48
Call Trace:
 <IRQ>  [<ffffffff8140c4fc>] sched_show_task+0x2cb/0x2d6 kernel/sched/core.c:5089
 [<ffffffff8140c787>] dump_cpu_task+0x79/0x7e kernel/sched/core.c:9046
 [<ffffffff81416c4d>] rcu_dump_cpu_stacks+0x150/0x164 kernel/rcu/tree.c:1233
 [<ffffffff8141784a>] print_cpu_stall kernel/rcu/tree.c:1340 [inline]
 [<ffffffff8141784a>] check_cpu_stall kernel/rcu/tree.c:1404 [inline]
 [<ffffffff8141784a>] __rcu_pending kernel/rcu/tree.c:3892 [inline]
 [<ffffffff8141784a>] rcu_pending kernel/rcu/tree.c:3956 [inline]
 [<ffffffff8141784a>] rcu_check_callbacks.cold.75+0x5c3/0xd20 kernel/rcu/tree.c:2796
 [<ffffffff8129a5aa>] update_process_times+0x3a/0x70 kernel/time/timer.c:1427
 [<ffffffff812c4f65>] tick_sched_handle.isra.15+0x55/0xf0 kernel/time/tick-sched.c:151
 [<ffffffff812c55f2>] tick_sched_timer+0x72/0x120 kernel/time/tick-sched.c:1097
 [<ffffffff8129db1d>] __run_hrtimer kernel/time/hrtimer.c:1261 [inline]
 [<ffffffff8129db1d>] __hrtimer_run_queues+0x3ad/0x1000 kernel/time/hrtimer.c:1325
 [<ffffffff8129f291>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1359
 [<ffffffff810ad554>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff838c2a8c>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff838c19d0>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI>  [<ffffffff834f8ea4>] ? _decode_session6+0x5a4/0x14d0 net/ipv6/xfrm6_policy.c:151
 [<ffffffff833c79a9>] __xfrm_decode_session+0x69/0x100 net/xfrm/xfrm_policy.c:2403
 [<ffffffff833d2317>] __xfrm_policy_check+0x137/0x1b30 net/xfrm/xfrm_policy.c:2440
 [<ffffffff8349724b>] __xfrm_policy_check2 include/net/xfrm.h:1067 [inline]
 [<ffffffff8349724b>] xfrm_policy_check include/net/xfrm.h:1076 [inline]
 [<ffffffff8349724b>] xfrm6_policy_check include/net/xfrm.h:1086 [inline]
 [<ffffffff8349724b>] udpv6_queue_rcv_skb+0x6bb/0x1500 net/ipv6/udp.c:634
 [<ffffffff82f2a21b>] sk_backlog_rcv include/net/sock.h:871 [inline]
 [<ffffffff82f2a21b>] __release_sock net/core/sock.c:2023 [inline]
 [<ffffffff82f2a21b>] release_sock+0x17b/0x500 net/core/sock.c:2473
 [<ffffffff832cece0>] udp_sendmsg+0x12b0/0x1bb0 net/ipv4/udp.c:1105
 [<ffffffff83494b49>] udpv6_sendmsg+0x1d59/0x24c0 net/ipv6/udp.c:1178
 [<ffffffff832fec53>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff82f1cd3c>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82f1cd3c>] sock_sendmsg+0xcc/0x110 net/socket.c:635
 [<ffffffff82f1cfa3>] sock_write_iter+0x223/0x3b0 net/socket.c:834
 [<ffffffff8151c5fd>] new_sync_write fs/read_write.c:478 [inline]
 [<ffffffff8151c5fd>] __vfs_write+0x30d/0x3f0 fs/read_write.c:491
 [<ffffffff8151e1e1>] vfs_write+0x191/0x4e0 fs/read_write.c:538
 [<ffffffff815207e9>] SYSC_write fs/read_write.c:585 [inline]
 [<ffffffff815207e9>] SyS_write+0xd9/0x1c0 fs/read_write.c:577
 [<ffffffff838bfe65>] entry_SYSCALL_64_fastpath+0x22/0x9e
INFO: rcu_sched detected stalls on CPUs/tasks:
	1-...: (12502 ticks this GP) idle=4ab/140000000000000/0 softirq=16332/16332 fqs=0 
	(detected by 0, t=12547 jiffies, g=-137, c=-138, q=1)
Task dump for CPU 1:
syz-executor2   R  running task    25872  7901   3935 0x0000000c
 0000000000000246 ffff8801d68468d8 0000000200000003 ffff8801d6846000
 ffffffff838c0a69 ffff88009d0e0010 ffff8800ba7e74e8 dffffc0000000000
 ffff8800ba7e7168 dffffc0000000000 ffff8800ba7e7178 ffffffff8122e576
Call Trace:
rcu_sched kthread starved for 12582 jiffies! g18446744073709551479 c18446744073709551478 f0x0 s3 ->state=0x1
INFO: task syz-executor4:3928 blocked for more than 120 seconds.
      Not tainted 4.4.131-gaa3863d #41
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D ffff8800a2f2f658 28176  3928   3914 0x00000000
 ffff8800a2f2f658 0000000000000000 ffff8801d9b8d0e0 ffffed003b371a1b
 ffff8801d9b8c800 ffff8801db21fdb8 ffff8801db21fde0 ffff8801db21f4d8
 ffff8801db21f4c0 ffffffff84417840 ffff8801d9b8c800 0000000000000000
Call Trace:
 [<ffffffff838b1e4a>] schedule+0x7a/0x1b0 kernel/sched/core.c:3359
 [<ffffffff838b25e3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3392
 [<ffffffff838b8727>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff838b8727>] mutex_lock_nested+0x307/0x850 kernel/locking/mutex.c:621
 [<ffffffff815d1c5c>] __blkdev_get+0x10c/0xdf0 fs/block_dev.c:1199
 [<ffffffff815d519a>] blkdev_get+0x2da/0x920 fs/block_dev.c:1353
 [<ffffffff815d59f5>] blkdev_open+0x1a5/0x250 fs/block_dev.c:1508
 [<ffffffff8151731b>] do_dentry_open+0x68b/0xbc0 fs/open.c:749
 [<ffffffff8151a94a>] vfs_open+0x12a/0x210 fs/open.c:862
 [<ffffffff8154b96e>] do_last fs/namei.c:3222 [inline]
 [<ffffffff8154b96e>] path_openat+0x4ee/0x3a10 fs/namei.c:3359
 [<ffffffff81551ba7>] do_filp_open+0x197/0x270 fs/namei.c:3393
 [<ffffffff8151b26c>] do_sys_open+0x31c/0x610 fs/open.c:1038
 [<ffffffff8151b58d>] SYSC_open fs/open.c:1056 [inline]
 [<ffffffff8151b58d>] SyS_open+0x2d/0x40 fs/open.c:1051
 [<ffffffff838bfe65>] entry_SYSCALL_64_fastpath+0x22/0x9e
1 lock held by syz-executor4/3928:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff815d1c5c>] __blkdev_get+0x10c/0xdf0 fs/block_dev.c:1199
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 491 Comm: khungtaskd Not tainted 4.4.131-gaa3863d #41
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bb3eb000 task.stack: ffff8800bb3f0000
RIP: 0010:[<ffffffff810bfda6>]  [<ffffffff810bfda6>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810bfda6>]  [<ffffffff810bfda6>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810bfda6>]  [<ffffffff810bfda6>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810bfda6>]  [<ffffffff810bfda6>] flat_send_IPI_mask+0xf6/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bb3f7cc8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fb300
RBP: ffff8800bb3f7cf0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000000000003 R14: 0000000000000002 R15: ffffffff8446f7a0
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001fa1000 CR3: 00000000b64e4000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8446f7a0 ffffffff84a18a20 0000000000000007 fffffbfff0942bf4
 0000000000000040 ffff8800bb3f7d10 ffffffff810b5d61 ffffffff83c0b1a0
 0000000000000003 ffff8800bb3f7d68 ffffffff81e19003 ffffffff8140d96f
Call Trace:
 [<ffffffff810b5d61>] nmi_raise_cpu_backtrace+0x61/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81e19003>] nmi_trigger_all_cpu_backtrace.cold.4+0x70/0xad lib/nmi_backtrace.c:85
 [<ffffffff810b5e04>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff8141a059>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff8141a059>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8141a059>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8141a059>] watchdog.cold.1+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff81190768>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838c0295>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
Code: b3 5f ff f6 c4 10 75 e2 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 f2 09 da 80 cf 04 41 83 fe 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 75 1a 4c 89 e7 57 9d 0f 1f 44 00 00 e8 62 
NMI backtrace for cpu 1
CPU: 1 PID: 7901 Comm: syz-executor2 Not tainted 4.4.131-gaa3863d #41
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d6846000 task.stack: ffff8800ba7e0000
RIP: 0010:[<ffffffff8135122b>]  [<ffffffff8135122b>] __write_once_size include/linux/compiler.h:247 [inline]
RIP: 0010:[<ffffffff8135122b>]  [<ffffffff8135122b>] __sanitizer_cov_trace_pc+0x4b/0x50 kernel/kcov.c:108
RSP: 0018:ffff8800ba7e7270  EFLAGS: 00000246
RAX: 0000000000040000 RBX: ffff8801d737b8c0 RCX: ffffc90007f4a000
RDX: 0000000000040000 RSI: ffffffff834f8ea4 RDI: ffff8801d737b93c
RBP: ffff8800ba7e7270 R08: ffffed0013a1dfe4 R09: ffffed0013a1dfe2
R10: ffffed0013a1dfe3 R11: ffff88009d0eff18 R12: 0000000000000000
R13: 000000000000ffe3 R14: ffff8800ba7e74e8 R15: dffffc0000000000
FS:  00007f5fcaf68700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000607304 CR3: 00000001d6d87000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8800ba7e7300 ffffffff834f8ea4 ffff88009d0e2921 ffff8801d737b990
 1ffff1003ae6f727 ffff8801d737b938 00000000000000f6 0000000000000000
 ffffed003ae6f732 ffff8801d737b988 ffff8801d737b97c 0000000000002910
Call Trace:
 [<ffffffff834f8ea4>] _decode_session6+0x5a4/0x14d0 net/ipv6/xfrm6_policy.c:151
 [<ffffffff833c79a9>] __xfrm_decode_session+0x69/0x100 net/xfrm/xfrm_policy.c:2403
 [<ffffffff833d2317>] __xfrm_policy_check+0x137/0x1b30 net/xfrm/xfrm_policy.c:2440
 [<ffffffff8349724b>] __xfrm_policy_check2 include/net/xfrm.h:1067 [inline]
 [<ffffffff8349724b>] xfrm_policy_check include/net/xfrm.h:1076 [inline]
 [<ffffffff8349724b>] xfrm6_policy_check include/net/xfrm.h:1086 [inline]
 [<ffffffff8349724b>] udpv6_queue_rcv_skb+0x6bb/0x1500 net/ipv6/udp.c:634
 [<ffffffff82f2a21b>] sk_backlog_rcv include/net/sock.h:871 [inline]
 [<ffffffff82f2a21b>] __release_sock net/core/sock.c:2023 [inline]
 [<ffffffff82f2a21b>] release_sock+0x17b/0x500 net/core/sock.c:2473
 [<ffffffff832cece0>] udp_sendmsg+0x12b0/0x1bb0 net/ipv4/udp.c:1105
 [<ffffffff83494b49>] udpv6_sendmsg+0x1d59/0x24c0 net/ipv6/udp.c:1178
 [<ffffffff832fec53>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff82f1cd3c>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82f1cd3c>] sock_sendmsg+0xcc/0x110 net/socket.c:635
 [<ffffffff82f1cfa3>] sock_write_iter+0x223/0x3b0 net/socket.c:834
 [<ffffffff8151c5fd>] new_sync_write fs/read_write.c:478 [inline]
 [<ffffffff8151c5fd>] __vfs_write+0x30d/0x3f0 fs/read_write.c:491
 [<ffffffff8151e1e1>] vfs_write+0x191/0x4e0 fs/read_write.c:538
 [<ffffffff815207e9>] SYSC_write fs/read_write.c:585 [inline]
 [<ffffffff815207e9>] SyS_write+0xd9/0x1c0 fs/read_write.c:577
 [<ffffffff838bfe65>] entry_SYSCALL_64_fastpath+0x22/0x9e
Code: 8b 90 98 12 00 00 83 fa 02 75 20 48 8b 88 a0 12 00 00 8b 80 9c 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 <5d> c3 0f 1f 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 89 f3