syzbot

INFO: task syz-executor.2:17717 blocked for more than 140 seconds.
      Not tainted 4.14.131+ #13
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29368 17717   1855 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:588 [inline]
 rwsem_down_write_failed+0x3b1/0x760 kernel/locking/rwsem-xadd.c:617
 call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:105
 __down_write arch/x86/include/asm/rwsem.h:126 [inline]
 down_write+0x4f/0x90 kernel/locking/rwsem.c:56
 inode_lock include/linux/fs.h:718 [inline]
 do_last fs/namei.c:3358 [inline]
 path_openat+0xdae/0x2b70 fs/namei.c:3597
 do_filp_open+0x1a1/0x280 fs/namei.c:3631
 do_sys_open+0x2ca/0x590 fs/open.c:1077
 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292

Showing all locks held in the system:
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<000000001f0b8d92>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
2 locks held by getty/1759:
 #0:  (&tty->ldisc_sem){++++}, at: [<000000003dfd818f>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<00000000f3c9fd56>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.2/17717:
 #0:  (sb_writers#4){.+.+}, at: [<000000001b15fd6e>] sb_start_write include/linux/fs.h:1549 [inline]
 #0:  (sb_writers#4){.+.+}, at: [<000000001b15fd6e>] mnt_want_write+0x3a/0xb0 fs/namespace.c:387
 #1:  (&type->i_mutex_dir_key#3){++++}, at: [<00000000b70524d6>] inode_lock include/linux/fs.h:718 [inline]
 #1:  (&type->i_mutex_dir_key#3){++++}, at: [<00000000b70524d6>] do_last fs/namei.c:3358 [inline]
 #1:  (&type->i_mutex_dir_key#3){++++}, at: [<00000000b70524d6>] path_openat+0xdae/0x2b70 fs/namei.c:3597

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

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.131+ #13
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x10e lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff8bc5e083