INFO: task syz-executor538:8110 blocked for more than 143 seconds.
      Not tainted 5.1.0-rc6+ #89
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor538 D28952  8110   7940 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2877 [inline]
 __schedule+0x813/0x1cc0 kernel/sched/core.c:3518
 schedule+0x92/0x180 kernel/sched/core.c:3562
 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:582 [inline]
 rwsem_down_write_failed+0x774/0xc30 kernel/locking/rwsem-xadd.c:611
 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117
 __down_write arch/x86/include/asm/rwsem.h:142 [inline]
 down_write+0x53/0x90 kernel/locking/rwsem.c:72
 grab_super+0xb4/0x290 fs/super.c:385
 sget_userns+0x1ab/0x560 fs/super.c:601
 sget+0x10c/0x150 fs/super.c:660
 mount_bdev+0xff/0x3c0 fs/super.c:1319
 udf_mount+0x35/0x40 fs/udf/super.c:131
 legacy_get_tree+0xf2/0x200 fs/fs_context.c:584
 vfs_get_tree+0x123/0x450 fs/super.c:1481
 do_new_mount fs/namespace.c:2622 [inline]
 do_mount+0x1436/0x2c40 fs/namespace.c:2942
 ksys_mount+0xdb/0x150 fs/namespace.c:3151
 __do_sys_mount fs/namespace.c:3165 [inline]
 __se_sys_mount fs/namespace.c:3162 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3162
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x44abd9
Code: 73 65 74 74 69 6e 67 00 00 49 6e 76 61 6c 69 64 20 22 24 41 63 74 69 6f 6e 51 75 65 75 65 44 65 71 75 65 75 65 54 69 6d 65 42 <65> 67 69 6e 22 2c 20 65 72 72 6f 72 20 25 64 2e 20 49 67 6e 6f 72
RSP: 002b:00007fb9bfbe2db8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000006dcc48 RCX: 000000000044abd9
RDX: 0000000020000240 RSI: 0000000020000200 RDI: 0000000020000080
RBP: 00000000006dcc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc4c
R13: 00007ffdfc4a9d8f R14: 00007fb9bfbe39c0 R15: 0000000000000001

Showing all locks held in the system:
1 lock held by khungtaskd/1034:
 #0: 000000004749f638 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5057
3 locks held by udevd/3874:
1 lock held by rsyslogd/7792:
 #0: 0000000087b839a2 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801
2 locks held by getty/7914:
 #0: 00000000ca28c403 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 000000008c85a92b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156
2 locks held by getty/7915:
 #0: 00000000597adbb1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 00000000619a6e03 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156
2 locks held by getty/7916:
 #0: 000000009e45b8d0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 00000000fb7e13b9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156
2 locks held by getty/7917:
 #0: 000000006acabd7b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 000000004c7dc31e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156
2 locks held by getty/7918:
 #0: 0000000052bace17 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 00000000293172de (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156
2 locks held by getty/7919:
 #0: 00000000bb80924d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 00000000a2b33058 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156
2 locks held by getty/7920:
 #0: 0000000017b7b423 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341
 #1: 0000000035cbffac (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156
1 lock held by syz-executor538/7956:
2 locks held by syz-executor538/8016:
2 locks held by syz-executor538/8098:
2 locks held by syz-executor538/8110:
 #0: 0000000076de43f3 (&bdev->bd_fsfreeze_mutex){+.+.}, at: mount_bdev+0x93/0x3c0 fs/super.c:1313
 #1: 00000000dafe6c9d (&type->s_umount_key#52){+.+.}, at: grab_super+0xb4/0x290 fs/super.c:385
2 locks held by blkid/11128:
 #0: 00000000cdf94dc0 (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0xbb/0x810 fs/block_dev.c:1833
 #1: 00000000c5b54113 (loop_ctl_mutex){+.+.}, at: __loop_clr_fd+0x88/0xd60 drivers/block/loop.c:1046
1 lock held by syz-executor538/11137:
 #0: 00000000cdf94dc0 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1513
1 lock held by syz-executor538/11144:
 #0: 00000000cdf94dc0 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1513
2 locks held by syz-executor538/11132:
 #0: 00000000a3b7c3de (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0xbb/0x810 fs/block_dev.c:1833
 #1: 00000000c5b54113 (loop_ctl_mutex){+.+.}, at: lo_release+0x1f/0x200 drivers/block/loop.c:1755
1 lock held by syz-executor538/11142:
 #0: 00000000f66a1384 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1513
2 locks held by syz-executor538/11133:
 #0: 000000001dcbb302 (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0xbb/0x810 fs/block_dev.c:1833
 #1: 00000000c5b54113 (loop_ctl_mutex){+.+.}, at: lo_release+0x1f/0x200 drivers/block/loop.c:1755
1 lock held by syz-executor538/11140:
 #0: 00000000093397ee (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1513
2 locks held by blkid/11138:
 #0: 00000000093397ee (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1513
 #1: 00000000c5b54113 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1736
2 locks held by blkid/11139:
 #0: 00000000f66a1384 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1513
 #1: 00000000c5b54113 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1736

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

NMI backtrace for cpu 1
CPU: 1 PID: 1034 Comm: khungtaskd Not tainted 5.1.0-rc6+ #89
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline]
 watchdog+0x9b7/0xec0 kernel/hung_task.c:288
 kthread+0x357/0x430 kernel/kthread.c:253
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 1 to CPUs 0: