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-executor7:15701 blocked for more than 120 seconds.
      Not tainted 4.9.106-g54f1dc0 #44
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D28584 15701   3890 0x00000004
 ffff880186e9c800 ffff8801b96f8000 ffff8801c8c90a80 ffff8801d95a9800
 ffff8801db321c18 ffff8801860d7580 ffffffff839e8c0d ffffffff81235b37
 0000000000000000 ffff880186e9d0c0 0000000600000007 ffff8801db3224e8
Call Trace:
 [<ffffffff839ea20f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f4634>] rwsem_down_read_failed+0x1e4/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81ee84d8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff839f3562>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff839f3562>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8157b109>] get_super.part.9+0x119/0x1f0 fs/super.c:665
 [<ffffffff8157b20b>] get_super+0x2b/0x50 include/linux/spinlock.h:302
 [<ffffffff81634087>] fsync_bdev+0x17/0xc0 fs/block_dev.c:214
 [<ffffffff81e5bd85>] invalidate_partition+0x35/0x60 block/genhd.c:1412
 [<ffffffff81e65327>] drop_partitions block/partition-generic.c:423 [inline]
 [<ffffffff81e65327>] rescan_partitions+0xc7/0x660 block/partition-generic.c:446
 [<ffffffff81e56804>] __blkdev_reread_part+0x164/0x1f0 block/ioctl.c:170
 [<ffffffff81e568b6>] blkdev_reread_part+0x26/0x40 block/ioctl.c:190
 [<ffffffff825c72cc>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:637
 [<ffffffff825c7d5e>] loop_set_status+0xa7e/0xfe0 drivers/block/loop.c:1171
 [<ffffffff825c875f>] loop_set_status64+0xbf/0x110 drivers/block/loop.c:1280
 [<ffffffff825caf66>] lo_ioctl+0x406/0x1aa0 drivers/block/loop.c:1370
 [<ffffffff81e57e26>] __blkdev_driver_ioctl block/ioctl.c:294 [inline]
 [<ffffffff81e57e26>] blkdev_ioctl+0x7b6/0x1a70 block/ioctl.c:590
 [<ffffffff81632f9e>] block_ioctl+0xde/0x120 fs/block_dev.c:1688
 [<ffffffff815b2fac>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b2fac>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b2fac>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b402f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b402f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9b13>] 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: [<ffffffff81366b6c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81366b6c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81426150>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3780:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f7cb2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821200e2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
3 locks held by syz-executor7/15701:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825cabeb>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
 #1:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff81e568ae>] blkdev_reread_part+0x1e/0x40 block/ioctl.c:189
 #2:  (&type->s_umount_key#49){++++..}, at: [<ffffffff8157b109>] get_super.part.9+0x119/0x1f0 fs/super.c:665
1 lock held by syz-executor7/15745:
 #0:  (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<ffffffff825cabeb>] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344
1 lock held by blkid/15709:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff816316ac>] __blkdev_get+0x10c/0xd60 fs/block_dev.c:1268

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.106-g54f1dc0 #44
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d85f7d08 ffffffff81eb4229 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b96a0 ffff8801d85f7d40
 ffffffff81ebf527 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4229>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4229>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebf527>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebf4ba>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b97a4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81367104>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81367104>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81367104>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81367104>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d04d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f9cdc>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 15691 Comm: syz-executor2 Not tainted 4.9.106-g54f1dc0 #44
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d61f9800 task.stack: ffff8801bc550000
RIP: 0010:[<ffffffff81624616>] 
c [<ffffffff81624616>] lookup_bh_lru fs/buffer.c:1327 [inline]
RIP: 0010:[<ffffffff81624616>] 
c [<ffffffff81624616>] __find_get_block+0x66/0x4c0 fs/buffer.c:1356
RSP: 0018:ffff8801bc557638  EFLAGS: 00000046
RAX: 0000000000040000 RBX: 0000000000000007 RCX: ffffc9000697e000
RDX: 0000000000040000 RSI: ffffffff81624616 RDI: ffff8801d5f73be8
RBP: ffff8801bc557678 R08: ffff8801d61fa110 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff1003ac3f41d R12: ffff8801d5f73bd0
R13: dffffc0000000000 R14: ffff8801d5f73bd0 R15: 0000000000000006
FS:  00007fc131a73700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c4296a7000 CR3: 00000001d85cf000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000020006f35b40
c 0000000000000052
c ffff8801b6422280
c 0000000000000001
c
 ffffea0006f35b5c
c ffffea0006f35b40
c 0000000000000200
c dffffc0000000000
c
 ffff8801bc557718
c ffffffff816255f9
c 0000000000000000
c ffff8801b6422288
c
Call Trace:
 [<ffffffff816255f9>] __getblk_slow fs/buffer.c:1101 [inline]
 [<ffffffff816255f9>] __getblk_gfp+0x189/0x710 fs/buffer.c:1386
 [<ffffffff81628f9d>] __bread_gfp+0x2d/0x270 fs/buffer.c:1420
 [<ffffffff818b71c8>] sb_bread include/linux/buffer_head.h:300 [inline]
 [<ffffffff818b71c8>] fat__get_entry+0x4c8/0x8f0 fs/fat/dir.c:100
 [<ffffffff818b9e51>] fat_get_entry fs/fat/dir.c:128 [inline]
 [<ffffffff818b9e51>] fat_get_short_entry+0x131/0x2a0 fs/fat/dir.c:876
 [<ffffffff818c1db7>] fat_subdirs+0xc7/0x190 fs/fat/dir.c:942
 [<ffffffff818d20c9>] fat_read_root fs/fat/inode.c:1402 [inline]
 [<ffffffff818d20c9>] fat_fill_super+0x1cf9/0x3550 fs/fat/inode.c:1832
 [<ffffffff818d8e81>] vfat_fill_super+0x31/0x40 fs/fat/namei_vfat.c:1070
 [<ffffffff8157c7e7>] mount_bdev+0x2c7/0x390 fs/super.c:1100
 [<ffffffff818d8e44>] vfat_mount+0x34/0x40 fs/fat/namei_vfat.c:1077
 [<ffffffff8157e56c>] mount_fs+0x28c/0x370 fs/super.c:1206
 [<ffffffff815ddd31>] vfs_kern_mount.part.29+0xd1/0x3d0 fs/namespace.c:991
 [<ffffffff815e5659>] vfs_kern_mount fs/namespace.c:973 [inline]
 [<ffffffff815e5659>] do_new_mount fs/namespace.c:2513 [inline]
 [<ffffffff815e5659>] do_mount+0x3c9/0x2740 fs/namespace.c:2835
 [<ffffffff815e83ae>] SYSC_mount fs/namespace.c:3051 [inline]
 [<ffffffff815e83ae>] SyS_mount+0xfe/0x110 fs/namespace.c:3028
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9b13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c<48> 
cc7 
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c01 
c