syzbot

random: cc1: uninitialized urandom read (8 bytes read)
audit: type=1400 audit(1556514747.661:9): avc:  denied  { map } for  pid=1944 comm="syz-execprog" path="/root/syzkaller-shm286186868" dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:file_t:s0 tclass=file permissive=1
INFO: task syz-executor.3:1964 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D25640  1964      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x4d9/0x1810 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
INFO: task syz-executor.4:1968 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D25640  1968      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 __lo_release drivers/block/loop.c:1644 [inline]
 lo_release+0x78/0x190 drivers/block/loop.c:1668
 __blkdev_put+0x518/0x6d0 fs/block_dev.c:1791
 blkdev_close+0x86/0xb0 fs/block_dev.c:1863
 __fput+0x25e/0x700 fs/file_table.c:210
 task_work_run+0x118/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
 do_syscall_64+0x372/0x4b0 arch/x86/entry/common.c:294
INFO: task syz-executor.5:1970 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D25144  1970      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x4d9/0x1810 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
INFO: task syz-executor.0:1973 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D25640  1973      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x4d9/0x1810 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
INFO: task syz-executor.1:1975 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D25160  1975      1 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x4d9/0x1810 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
INFO: task blkid:3006 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D29048  3006    293 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x4d9/0x1810 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
INFO: task blkid:3008 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D27800  3008   2926 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x4d9/0x1810 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
INFO: task syz-executor.2:3009 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28648  3009   1961 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x72/0x80 drivers/block/loop.c:615
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1184
INFO: task blkid:3010 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D27800  3010   2862 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x4d9/0x1810 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
INFO: task blkid:3014 blocked for more than 140 seconds.
      Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28328  3014   2921 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1624
 __blkdev_get+0x963/0xf90 fs/block_dev.c:1537
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xdf0 fs/open.c:770
 vfs_open+0x105/0x230 fs/open.c:884
 do_last fs/namei.c:3455 [inline]
 path_openat+0xb6b/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/0x4b0 arch/x86/entry/common.c:289

Showing all locks held in the system:
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<        (ptrval)>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
1 lock held by rsyslogd/1627:
 #0:  (&f->f_pos_lock){+.+.}, at: [<        (ptrval)>] __fdget_pos+0xa6/0xc0 fs/file.c:769
2 locks held by getty/1755:
 #0:  (&tty->ldisc_sem){++++}, at: [<        (ptrval)>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<        (ptrval)>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.3/1964:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
3 locks held by syz-executor.4/1968:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_release+0x19/0x190 drivers/block/loop.c:1667
 #2:  (loop_ctl_mutex#2){+.+.}, at: [<        (ptrval)>] __lo_release drivers/block/loop.c:1644 [inline]
 #2:  (loop_ctl_mutex#2){+.+.}, at: [<        (ptrval)>] lo_release+0x78/0x190 drivers/block/loop.c:1668
1 lock held by syz-executor.5/1970:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
1 lock held by syz-executor.0/1973:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
1 lock held by syz-executor.1/1975:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
1 lock held by blkid/3006:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
1 lock held by blkid/3008:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
2 locks held by syz-executor.2/3009:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
 #1:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
1 lock held by blkid/3010:
 #0:  (loop_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405
2 locks held by blkid/3014:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1624
2 locks held by blkid/3015:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1624
1 lock held by blkid/3016:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457

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

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.113+ #61
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 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff9424ece2