pktgen: kernel_thread() failed for cpu 0
pktgen: Cannot create thread for cpu 0 (-4)
pktgen: kernel_thread() failed for cpu 1
pktgen: Cannot create thread for cpu 1 (-4)
pktgen: Initialization failed for all threads
INFO: task syz-executor0:8553 blocked for more than 140 seconds.
      Not tainted 4.9.118-g47b77b8 #20
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D28904  8553   3858 0x00000004
 ffff880198204800 ffff8801bc361500 ffff8801c825b480 ffff88019e1b3000
 ffff8801db321c18 ffff8801ca62f660 ffffffff839ebbad dffffc0000000000
 ffff8801cbdda270 ffff8801ca62f620 00ff8801982050c0 ffff8801db3224e8
Call Trace:
 [<ffffffff839ed1af>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff815c80a2>] d_wait_lookup fs/dcache.c:2455 [inline]
 [<ffffffff815c80a2>] d_alloc_parallel+0xeb2/0x17c0 fs/dcache.c:2537
 [<ffffffff8159505c>] lookup_slow+0x19c/0x470 fs/namei.c:1650
 [<ffffffff815a1686>] walk_component+0x716/0x1bb0 fs/namei.c:1784
 [<ffffffff815a3fe6>] lookup_last fs/namei.c:2266 [inline]
 [<ffffffff815a3fe6>] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283
 [<ffffffff815a9a97>] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317
 [<ffffffff815a9e53>] filename_lookup fs/namei.c:2310 [inline]
 [<ffffffff815a9e53>] user_path_at_empty+0x53/0x70 fs/namei.c:2578
 [<ffffffff8161c10f>] user_path_at include/linux/namei.h:55 [inline]
 [<ffffffff8161c10f>] do_utimes+0x17f/0x2c0 fs/utimes.c:155
 [<ffffffff8161c7ed>] SYSC_futimesat fs/utimes.c:214 [inline]
 [<ffffffff8161c7ed>] SyS_futimesat fs/utimes.c:189 [inline]
 [<ffffffff8161c7ed>] SYSC_utimes fs/utimes.c:220 [inline]
 [<ffffffff8161c7ed>] SyS_utimes+0x13d/0x1b0 fs/utimes.c:217
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fca93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/520:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136679c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136679c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425fb7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3762:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fac52>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff821207a2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor0/8547:
 #0:  (&sb->s_type->i_mutex_key#20){++++++}, at: [<ffffffff81595001>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#20){++++++}, at: [<ffffffff81595001>] lookup_slow+0x141/0x470 fs/namei.c:1645
1 lock held by syz-executor0/8553:
 #0:  (&sb->s_type->i_mutex_key#20){++++++}, at: [<ffffffff81595001>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#20){++++++}, at: [<ffffffff81595001>] lookup_slow+0x141/0x470 fs/namei.c:1645

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 520 Comm: khungtaskd Not tainted 4.9.118-g47b77b8 #20
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8a4fd08 ffffffff81eb4b89 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9bd0 ffff8801d8a4fd40
 ffffffff81ebfe87 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4b89>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4b89>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebfe87>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebfe1a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366d34>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d34>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d34>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d34>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fcc5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 25 Comm: kworker/0:1 Not tainted 4.9.118-g47b77b8 #20
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient gc_worker
c
task: ffff8801d9408000 task.stack: ffff8801d9410000
RIP: 0010:[<ffffffff831f4f58>] 
c [<ffffffff831f4f58>] arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
RIP: 0010:[<ffffffff831f4f58>] 
c [<ffffffff831f4f58>] seqcount_lockdep_reader_access include/linux/seqlock.h:82 [inline]
RIP: 0010:[<ffffffff831f4f58>] 
c [<ffffffff831f4f58>] read_seqcount_begin include/linux/seqlock.h:163 [inline]
RIP: 0010:[<ffffffff831f4f58>] 
c [<ffffffff831f4f58>] nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:325 [inline]
RIP: 0010:[<ffffffff831f4f58>] 
c [<ffffffff831f4f58>] gc_worker+0x198/0x620 net/netfilter/nf_conntrack_core.c:968
RSP: 0018:ffff8801d9417bd0  EFLAGS: 00000293
RAX: 0000000000000007 RBX: 0000000000000293 RCX: 1ffff1003b281122
RDX: 0000000000000000 RSI: ffff8801d9408918 RDI: 0000000000000293
RBP: ffff8801d9417c40 R08: ffff8801d9408910 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffffff84c65ba0 R14: ffffffff84c65ba8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000cff000 CR3: 00000001bc2e0000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8118d181
c ffffffff864ef378
c ffffffff864ef2c0
c fffffbfff08c1200
c
 00000200da086d00
c ffff880100010000
c ffff8801ce3b49d8
c 0000693c00000000
c
 000000000000013b
c ffffffff864ef2c0
c ffff8801d9417cd0
c ffff8801da086d18
c
Call Trace:
 [<ffffffff8118d181>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118df76>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fcc5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
c04 
cfe 
c48 
c8b 
c55 
c08 
cbe 
c01 
c00 
c00 
c00 
c4c 
c89 
cf7 
ce8 
ce0 
c5f 
c04 
cfe 
cf6 
cc7 
c02 
c0f 
c84 
c67 
cff 
cff 
cff 
ce8 
c62 
c9b 
c16 
cfe 
ce8 
ccd 
c0c 
c04 
cfe 
c48 
c89 
cdf 
c57 
c9d 
c<0f> 
c1f 
c44 
c00 
c00 
ce8 
c4e 
c9b 
c16 
cfe 
c41 
c8b 
c5d 
c00 
cf6 
cc3 
c01 
c0f 
c84 
c67 
cff 
c