b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
INFO: task syz-executor1:8538 blocked for more than 120 seconds.
      Not tainted 4.9.98-ga03d0bb #18
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D29800  8538   3894 0x00000004
 ffff8801c5efc800 ffff8801c3d6b9c0 ffff8801c9c10000 ffff8801d8371800
 ffff8801db321b98 ffff8801d96a7bc8 ffffffff839e377d ffff8801c5efd0c8
 ffffed0038bdfa18 ffff8801c5efc800 00fffc0000000000 ffff8801db322468
Call Trace:
 [<ffffffff839e4d7f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839e5703>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3590
 [<ffffffff839e9b86>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff839e9b86>] mutex_lock_nested+0x326/0x870 kernel/locking/mutex.c:621
 [<ffffffff83058fb5>] copy_net_ns+0x155/0x290 net/core/net_namespace.c:406
 [<ffffffff8119e3cc>] create_new_namespaces+0x51c/0x730 kernel/nsproxy.c:106
 [<ffffffff8119ebc5>] unshare_nsproxy_namespaces+0xa5/0x1d0 kernel/nsproxy.c:205
 [<ffffffff811333e9>] SYSC_unshare kernel/fork.c:2244 [inline]
 [<ffffffff811333e9>] SyS_unshare+0x319/0x710 kernel/fork.c:2194
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4653>] 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: [<ffffffff813646ec>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813646ec>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81423ba0>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3674:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d565c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3771:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f2822>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211cbb2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor1/8538:
 #0:  (net_mutex){+.+.+.}, at: [<ffffffff83058fb5>] copy_net_ns+0x155/0x290 net/core/net_namespace.c:406
2 locks held by syz-executor0/8533:
 #0:  (sb_writers#15){.+.+.+}, at: [<ffffffff815ddeff>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers#15){.+.+.+}, at: [<ffffffff815ddeff>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff815a2dec>] inode_lock_shared include/linux/fs.h:776 [inline]
 #1:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff815a2dec>] do_last fs/namei.c:3314 [inline]
 #1:  (&sb->s_type->i_mutex_key#15){++++++}, at: [<ffffffff815a2dec>] path_openat+0x17dc/0x3590 fs/namei.c:3534
1 lock held by init/8542:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/8543:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/8544:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/8545:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/8546:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125
1 lock held by init/8547:
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open_by_driver drivers/tty/tty_io.c:2047 [inline]
 #0:  (tty_mutex){+.+.+.}, at: [<ffffffff82116c5c>] tty_open+0x46c/0xe20 drivers/tty/tty_io.c:2125

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.98-ga03d0bb #18
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d87a7d08 ffffffff81eb0e89 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b7da0 ffff8801d87a7d40
 ffffffff81ebc187 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb0e89>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb0e89>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebc187>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebc11a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b7ea4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81364c84>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81364c84>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81364c84>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81364c84>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119ad5d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f481c>] 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: 8466 Comm: syz-executor1 Not tainted 4.9.98-ga03d0bb #18
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88018eeb4800 task.stack: ffff8801d7450000
RIP: 0010:[<ffffffff8214d50b>] 
c [<ffffffff8214d50b>] inb arch/x86/include/asm/io.h:316 [inline]
RIP: 0010:[<ffffffff8214d50b>] 
c [<ffffffff8214d50b>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:414
RSP: 0018:ffff8801d7457768  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff8214d4b1 RDI: ffffffff864aae78
RBP: ffff8801d7457778 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff864aae40
R13: 0000000000000020 R14: fffffbfff0c9560f R15: fffffbfff0c955d1
FS:  00007f0359328700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5c9e9e7f32 CR3: 00000001bf5f0000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff864aae40
c 000000000000270b
c ffff8801d74577c8
c ffffffff8214f0d4
c
 ffffffff81edc178
c ffffffff864aae88
c ffffffff864ab07a
c ffffffff864aae40
c
 0000000000000032
c ffffffff8214f220
c dffffc0000000000
c 0000000000000032
c
Call Trace:
 [<ffffffff8214f0d4>] serial_in drivers/tty/serial/8250/8250.h:111 [inline]
 [<ffffffff8214f0d4>] wait_for_xmitr+0x94/0x1e0 drivers/tty/serial/8250/8250_port.c:1997
 [<ffffffff8214f23f>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:3103
 [<ffffffff82137a69>] uart_console_write+0x59/0xf0 drivers/tty/serial/serial_core.c:1859
 [<ffffffff8215b448>] serial8250_console_write+0x528/0x820 drivers/tty/serial/8250/8250_port.c:3169
 [<ffffffff82147fbf>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff81259e7d>] call_console_drivers.isra.18.constprop.28+0x1ad/0x360 kernel/printk/printk.c:1589
 [<ffffffff8125cc7f>] console_unlock+0x42f/0xb40 kernel/printk/printk.c:2449
 [<ffffffff8125d7d8>] vprintk_emit+0x448/0x790 kernel/printk/printk.c:1903
 [<ffffffff8125db48>] vprintk+0x28/0x30 kernel/printk/printk.c:1913
 [<ffffffff8125db6d>] vprintk_default+0x1d/0x30 kernel/printk/printk.c:1914
 [<ffffffff8142a975>] vprintk_func kernel/printk/internal.h:36 [inline]
 [<ffffffff8142a975>] printk+0xaf/0xd7 kernel/printk/printk.c:1975
 [<ffffffff839cd5b0>] __ip_vs_init.cold.37+0x36/0x45 net/netfilter/ipvs/ip_vs_core.c:2243
 [<ffffffff830576bc>] ops_init+0xac/0x380 net/core/net_namespace.c:111
 [<ffffffff83057b49>] setup_net+0x1b9/0x3f0 net/core/net_namespace.c:291
 [<ffffffff83058fe9>] copy_net_ns+0x189/0x290 net/core/net_namespace.c:408
 [<ffffffff8119e3cc>] create_new_namespaces+0x51c/0x730 kernel/nsproxy.c:106
 [<ffffffff8119ebc5>] unshare_nsproxy_namespaces+0xa5/0x1d0 kernel/nsproxy.c:205
 [<ffffffff811333e9>] SYSC_unshare kernel/fork.c:2244 [inline]
 [<ffffffff811333e9>] SyS_unshare+0x319/0x710 kernel/fork.c:2194
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4653>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
c24 
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c<5b> 
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c