syzbot

IPVS: Creating netns size=2536 id=72
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=8241 sclass=netlink_route_socket pig=27416 comm=syz-executor6
INFO: task syz-executor3:27332 blocked for more than 140 seconds.
      Not tainted 4.9.112-g9e79039 #59
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3   D21560 27332   3867 0x00000004
 ffff8801ca1b1800 ffff8801cecf8a80 ffff8801cf686f40 ffff8801ca1b6000
 ffff8801db221c18 ffff8801a241f8f0 ffffffff839e907d 0000000041b58ab3
 ffffffff843c36c0 ffffffff812361d0 00ff8801ca1b20c8 ffff8801db2224e8
Call Trace:
 [<ffffffff839ea67f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3557
 [<ffffffff839f6a91>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
 [<ffffffff839e885a>] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5180
 [<ffffffff839ebac9>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff839ebac9>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff839eb36e>] __wait_on_bit_lock+0xce/0x1c0 kernel/sched/wait.c:421
 [<ffffffff8143464f>] __lock_page+0xff/0x160 mm/filemap.c:934
 [<ffffffff8146b8a8>] lock_page include/linux/pagemap.h:454 [inline]
 [<ffffffff8146b8a8>] truncate_inode_pages_range+0x818/0x1290 mm/truncate.c:373
 [<ffffffff816329dd>] blkdev_fallocate+0x21d/0x440 fs/block_dev.c:1817
 [<ffffffff81568809>] vfs_fallocate+0x359/0x600 fs/open.c:329
 [<ffffffff8156b713>] SYSC_fallocate fs/open.c:352 [inline]
 [<ffffffff8156b713>] SyS_fallocate+0x53/0x90 fs/open.c:346
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] 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: [<ffffffff8136675c>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136675c>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81425de7>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3684:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d818c>] __fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3780:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839f8122>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211edc2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor3/27332:
 #0:  (sb_writers){.+.+.+}, at: [<ffffffff815687ab>] sb_start_write include/linux/fs.h:1573 [inline]
 #0:  (sb_writers){.+.+.+}, at: [<ffffffff815687ab>] vfs_fallocate+0x2fb/0x600 fs/open.c:328

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

NMI backtrace for cpu 0
CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.112-g9e79039 #59
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d85efd08 ffffffff81eb3249 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810b9bd0 ffff8801d85efd40
 ffffffff81ebe547 0000000000000000 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb3249>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3249>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebe547>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebe4da>] 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
 [<ffffffff81366cf4>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366cf4>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366cf4>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366cf4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0bd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fa11c>] 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: 27455 Comm: init Not tainted 4.9.112-g9e79039 #59
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801a0921800 task.stack: ffff8801cb020000
RIP: 0010:[<ffffffff8214fafb>] 
c [<ffffffff8214fafb>] inb arch/x86/include/asm/io.h:316 [inline]
RIP: 0010:[<ffffffff8214fafb>] 
c [<ffffffff8214fafb>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:414
RSP: 0018:ffff8801cb027520  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffffff8214faa1 RDI: ffffffff864aae78
RBP: ffff8801cb027530 R08: ffff8801a0922138 R09: 0000000000000001
R10: ffff8801a0921800 R11: 1ffff10034124422 R12: ffffffff864aae40
R13: 0000000000000020 R14: fffffbfff0c9560f R15: fffffbfff0c955d1
FS:  00007f94d3b647a0(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f94d3277a30 CR3: 00000001cc0e5000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff864aae40
c 000000000000270d
c ffff8801cb027580
c ffffffff821516c4
c
 ffff8801cb0275b8
c ffffffff864aae88
c ffffffff864ab07a
c ffffffff864aae40
c
 0000000000000038
c ffffffff82151810
c dffffc0000000000
c 0000000000000038
c
Call Trace:
 [<ffffffff821516c4>] serial_in drivers/tty/serial/8250/8250.h:111 [inline]
 [<ffffffff821516c4>] wait_for_xmitr+0x94/0x1e0 drivers/tty/serial/8250/8250_port.c:1998
 [<ffffffff8215182f>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:3104
 [<ffffffff8213a059>] uart_console_write+0x59/0xf0 drivers/tty/serial/serial_core.c:1859
 [<ffffffff8215da48>] serial8250_console_write+0x528/0x820 drivers/tty/serial/8250/8250_port.c:3170
 [<ffffffff8214a5af>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff8125bccd>] call_console_drivers.isra.18.constprop.28+0x1ad/0x360 kernel/printk/printk.c:1589
 [<ffffffff8125eacf>] console_unlock+0x42f/0xb40 kernel/printk/printk.c:2449
 [<ffffffff8125ff17>] console_device+0x97/0xc0 kernel/printk/printk.c:2557
 [<ffffffff8211947a>] tty_lookup_driver drivers/tty/tty_io.c:2003 [inline]
 [<ffffffff8211947a>] tty_open_by_driver drivers/tty/tty_io.c:2048 [inline]
 [<ffffffff8211947a>] tty_open+0x71a/0xe20 drivers/tty/tty_io.c:2125
 [<ffffffff8157ee6d>] chrdev_open+0x22d/0x4c0 fs/char_dev.c:392
 [<ffffffff81569d53>] do_dentry_open+0x703/0xc80 fs/open.c:766
 [<ffffffff8156d53c>] vfs_open+0x11c/0x210 fs/open.c:879
 [<ffffffff815a4678>] do_last fs/namei.c:3410 [inline]
 [<ffffffff815a4678>] path_openat+0x758/0x3590 fs/namei.c:3534
 [<ffffffff815ab777>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff8156df4d>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff8156e22d>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8156e22d>] SyS_open+0x2d/0x40 fs/open.c:1085
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c