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
IPVS: Creating netns size=2536 id=44
INFO: task syz-executor1:14723 blocked for more than 140 seconds.
      Not tainted 4.9.119-g9dc978d #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D29256 14723  11739 0x00000004
 ffff8801d0663000 0000000000000000 ffff8801d8a58fc0 ffff8801d9bd0000
 ffff8801db221c18 ffff88019ba27b58 ffffffff839ebdcd 0000000000000002
 0000000041b58ab3 ffffffff843bc37b 00ffffff81221590 ffff8801db2224e8
Call Trace:
 [<ffffffff839ed3cf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff81603039>] wb_wait_for_completion+0x149/0x1b0 fs/fs-writeback.c:221
 [<ffffffff816087c9>] sync_inodes_sb+0x1a9/0x8d0 fs/fs-writeback.c:2412
 [<ffffffff8161a8f3>] sync_inodes_one_sb+0x43/0x60 fs/sync.c:73
 [<ffffffff8157d1b0>] iterate_supers+0x130/0x260 fs/super.c:593
 [<ffffffff8161b202>] sys_sync+0xa2/0x170 fs/sync.c:112
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667bc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667bc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81426027>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3625:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fae72>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821208d2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor1/14723:
 #0:  (&type->s_umount_key#46){++++..}, at: [<ffffffff8157d161>] iterate_supers+0xe1/0x260 fs/super.c:591
1 lock held by syz-executor1/14784:
 #0:  (&type->s_umount_key#46){++++..}, at: [<ffffffff8157d161>] iterate_supers+0xe1/0x260 fs/super.c:591

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8a7fd08 ffffffff81eb4be9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9bd0 ffff8801d8a7fd40
 ffffffff81ebfee7 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4be9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4be9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebfee7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebfe7a>] 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
 [<ffffffff81366d54>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d54>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d54>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d54>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fce9c>] 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: 4904 Comm: kworker/u4:6 Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn
c (flush-7:0)
c
task: ffff88019906c800 task.stack: ffff880198b20000
RIP: 0010:[<ffffffff81230995>] 
c [<ffffffff81230995>] lock_is_held+0x15/0x140 kernel/locking/lockdep.c:3783
RSP: 0018:ffff880198b274f0  EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffff88019906c800 RCX: ffff88019906c800
RDX: 0000000000000000 RSI: ffffffff846def60 RDI: ffffffff846def20
RBP: ffff880198b27500 R08: ffff88019906d160 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003320da27 R12: 0000000000000000
R13: ffffffff846def20 R14: 00000000000001cc R15: ffff8801d61a42c8
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdc0f23f000 CR3: 00000001c9c03000 CR4: 00000000001606f0
DR0: ffffffffffffffff DR1: ffffffffffffffff DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Stack:
 0000000000000000
c ffffffff83ca47a0
c ffff880198b27538
c ffffffff811bb597
c
 ffff88019906c800
c ffffffff83ca47a0
c 00000000000001cc
c 0000000000000000
c
 ffff8801d61a42c8
c ffff880198b27578
c ffffffff811bb6c5
c ffffea000740e100
c
Call Trace:
 [<ffffffff811bb597>] ___might_sleep+0x1c7/0x260 kernel/sched/core.c:7954
 [<ffffffff811bb6c5>] __might_sleep+0x95/0x1a0 kernel/sched/core.c:7945
 [<ffffffff8143a65d>] lock_page include/linux/pagemap.h:460 [inline]
 [<ffffffff8143a65d>] pagecache_get_page+0x3bd/0x720 mm/filemap.c:1214
 [<ffffffff81625809>] find_or_create_page include/linux/pagemap.h:309 [inline]
 [<ffffffff81625809>] grow_dev_page fs/buffer.c:1005 [inline]
 [<ffffffff81625809>] grow_buffers fs/buffer.c:1078 [inline]
 [<ffffffff81625809>] __getblk_slow fs/buffer.c:1105 [inline]
 [<ffffffff81625809>] __getblk_gfp+0x249/0x710 fs/buffer.c:1386
 [<ffffffff816290ed>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818cc60b>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818cc60b>] __fat_write_inode+0x2ab/0x980 fs/fat/inode.c:852
 [<ffffffff818d08c9>] fat_write_inode+0x79/0x170 fs/fat/inode.c:901
 [<ffffffff8160273d>] write_inode fs/fs-writeback.c:1180 [inline]
 [<ffffffff8160273d>] __writeback_single_inode+0x86d/0x1020 fs/fs-writeback.c:1379
 [<ffffffff81603a3c>] writeback_sb_inodes+0x4ac/0xe70 fs/fs-writeback.c:1584
 [<ffffffff816044fb>] __writeback_inodes_wb+0xfb/0x1e0 fs/fs-writeback.c:1653
 [<ffffffff81604c82>] wb_writeback+0x512/0xbd0 fs/fs-writeback.c:1762
 [<ffffffff8160e5b0>] wb_check_old_data_flush fs/fs-writeback.c:1877 [inline]
 [<ffffffff8160e5b0>] wb_do_writeback fs/fs-writeback.c:1901 [inline]
 [<ffffffff8160e5b0>] wb_workfn+0x850/0xdb0 fs/fs-writeback.c:1930
 [<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
 [<ffffffff839fce9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Code: 
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c