syzbot


INFO: task hung in loop_control_ioctl

Status: public: reported C repro on 2019/04/13 00:01
Reported-by: syzbot+21bb5a0b4224d5d24925@syzkaller.appspotmail.com
First crash: 2244d, last: 1852d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in loop_control_ioctl block 4 2233d 2426d 11/28 fixed on 2019/01/15 20:25
android-49 INFO: task hung in loop_control_ioctl C 59 1821d 2050d 0/3 public: reported C repro on 2019/04/12 00:00
linux-4.14 INFO: task hung in loop_control_ioctl (2) C inconclusive 7 805d 1726d 0/1 upstream: reported C repro on 2020/02/29 17:00
android-44 INFO: task hung in loop_control_ioctl 6 2393d 2517d 0/2 auto-closed as invalid on 2019/02/22 15:22
linux-4.14 INFO: task hung in loop_control_ioctl 1 1883d 1883d 0/1 auto-closed as invalid on 2020/01/24 04:19

Sample crash report:
INFO: task syz-executor694:1954 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor694 D26960  1954   1913 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+0x595/0x13e0 kernel/locking/mutex.c:893
 loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1996
 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/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441869
RSP: 002b:00007ffc3ac8f738 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441869
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 00000000000cd01c R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000402580
R13: 0000000000402610 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor694:1955 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor694 D26960  1955   1912 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+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_release+0x1b/0x1a0 drivers/block/loop.c:1666
 __blkdev_put+0x518/0x6d0 fs/block_dev.c:1791
 blkdev_close+0x86/0xb0 fs/block_dev.c:1863
 __fput+0x25e/0x710 fs/file_table.c:210
 task_work_run+0x125/0x1a0 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:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4014a0
RSP: 002b:00007ffc3ac8f4f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000004014a0
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000000c
R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
INFO: task blkid:1961 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28624  1961   1922 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+0x595/0x13e0 kernel/locking/mutex.c:893
 blkdev_put+0x27/0x4c0 fs/block_dev.c:1814
 blkdev_close+0x86/0xb0 fs/block_dev.c:1863
 __fput+0x25e/0x710 fs/file_table.c:210
 task_work_run+0x125/0x1a0 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:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f5b6a2c92b0
RSP: 002b:00007fffc6e4e518 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f5b6a2c92b0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000018be030
R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005
INFO: task blkid:1964 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28624  1964   1928 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+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_release+0x1b/0x1a0 drivers/block/loop.c:1666
 __blkdev_put+0x518/0x6d0 fs/block_dev.c:1791
 blkdev_close+0x86/0xb0 fs/block_dev.c:1863
 __fput+0x25e/0x710 fs/file_table.c:210
 task_work_run+0x125/0x1a0 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:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f8af846e2b0
RSP: 002b:00007ffd9f3c3d68 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f8af846e2b0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000211b030
R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005
INFO: task syz-executor694:1965 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor694 D28336  1965   1907 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+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x401500
RSP: 002b:00007ffc3ac8f4f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000020000168 RCX: 0000000000401500
RDX: 00007ffc3ac8f68a RSI: 0000000000000002 RDI: 00007ffc3ac8f680
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
INFO: task blkid:1966 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28896  1966    309 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+0x595/0x13e0 kernel/locking/mutex.c:893
 __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f5db60c4120
RSP: 002b:00007ffe177f4368 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5db60c4120
RDX: 00007ffe177f5f41 RSI: 0000000000000000 RDI: 00007ffe177f5f41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000cd5030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task syz-executor694:1967 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor694 D28624  1967   1905 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+0x595/0x13e0 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7f/0x90 drivers/block/loop.c:614
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa5/0x100 drivers/block/loop.c:1301
 lo_ioctl+0xd1/0x1a30 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x8d0/0x1870 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/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441777
RSP: 002b:00007ffc3ac8f4f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000020000168 RCX: 0000000000441777
RDX: 00007ffc3ac8f590 RSI: 0000000000004c04 RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor694:1968 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor694 D28624  1968   1906 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+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x401500
RSP: 002b:00007ffc3ac8f4f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000020000168 RCX: 0000000000401500
RDX: 00007ffc3ac8f68a RSI: 0000000000000002 RDI: 00007ffc3ac8f680
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor694:1969 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor694 D27360  1969   1914 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+0x595/0x13e0 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7f/0x90 drivers/block/loop.c:614
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa5/0x100 drivers/block/loop.c:1301
 lo_ioctl+0xd1/0x1a30 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x8d0/0x1870 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/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441777
RSP: 002b:00007ffc3ac8f4f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000020000168 RCX: 0000000000441777
RDX: 00007ffc3ac8f590 RSI: 0000000000004c04 RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
INFO: task blkid:1972 blocked for more than 140 seconds.
      Not tainted 4.14.150+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D27808  1972   1921 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+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __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/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f40b997b120
RSP: 002b:00007ffeeaa75888 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f40b997b120
RDX: 00007ffeeaa76f41 RSI: 0000000000000000 RDI: 00007ffeeaa76f41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001230030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005

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
2 locks held by getty/1763:
 #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
2 locks held by syz-executor694/1954:
 #0:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982
 #1:  (&lo->lo_ctl_mutex#2){+.+.}, at: [<        (ptrval)>] loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1996
2 locks held by syz-executor694/1955:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_release+0x1b/0x1a0 drivers/block/loop.c:1666
1 lock held by blkid/1961:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] blkdev_put+0x27/0x4c0 fs/block_dev.c:1814
2 locks held by blkid/1964:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_release+0x1b/0x1a0 drivers/block/loop.c:1666
2 locks held by syz-executor694/1965:
 #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:1623
1 lock held by blkid/1966:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
2 locks held by syz-executor694/1967:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by syz-executor694/1968:
 #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:1623
2 locks held by syz-executor694/1969:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by blkid/1972:
 #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:1623
1 lock held by blkid/1973:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
2 locks held by blkid/1974:
 #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:1623

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

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.150+ #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x119/0x147 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x629/0xbe0 kernel/hung_task.c:274
 kthread+0x31f/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffffaa2a45f3

Crashes (23):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/10/27 05:03 android-4.14 2d0e4c21fcee 25bb509e .config console log report syz C ci-android-414-kasan-gce-root
2019/10/06 05:00 android-4.14 ed203b32ee7e f3f7d9c8 .config console log report ci-android-414-kasan-gce-root
2019/09/18 20:53 android-4.14 6bb0e9159cb6 c2dcd700 .config console log report ci-android-414-kasan-gce-root
2019/08/06 03:03 android-4.14 889977e308d1 6affd8e8 .config console log report ci-android-414-kasan-gce-root
2019/03/18 17:33 android-4.14 8ed9bc6e6401 4656beca .config console log report ci-android-414-kasan-gce-root
2019/03/15 17:08 android-4.14 8ed9bc6e6401 bab43553 .config console log report ci-android-414-kasan-gce-root
2019/01/15 17:23 android-4.14 8fccd8d9d51a 79cb1a7c .config console log report ci-android-414-kasan-gce-root
2019/01/13 16:54 android-4.14 da2880fa47ec c3f3344c .config console log report ci-android-414-kasan-gce-root
2019/01/10 05:45 android-4.14 2aee898fff5a 45c0c1b1 .config console log report ci-android-414-kasan-gce-root
2019/01/05 06:01 android-4.14 3c207c880674 53be0a37 .config console log report ci-android-414-kasan-gce-root
2018/12/25 22:07 android-4.14 815e34f802d8 8a41a0ad .config console log report ci-android-414-kasan-gce-root
2018/12/12 13:49 android-4.14 e525d2cfbe65 c3b10a5d .config console log report ci-android-414-kasan-gce-root
2018/12/12 11:54 android-4.14 e525d2cfbe65 c3b10a5d .config console log report ci-android-414-kasan-gce-root
2018/12/05 10:41 android-4.14 d11d7f1ccfb1 ac6c0578 .config console log report ci-android-414-kasan-gce-root
2018/12/01 05:34 android-4.14 51164110fa6e d8988561 .config console log report ci-android-414-kasan-gce-root
2018/11/18 08:54 android-4.14 4e76528bd48d adf636a8 .config console log report ci-android-414-kasan-gce-root
2018/11/12 20:33 android-4.14 494c2659e60e 74dbb806 .config console log report ci-android-414-kasan-gce-root
2018/11/08 17:21 android-4.14 d4e5dea08bbf e85d2a61 .config console log report ci-android-414-kasan-gce-root
2018/11/03 06:26 android-4.14 12064f3a794e 8bd6bd63 .config console log report ci-android-414-kasan-gce-root
2018/11/01 18:37 android-4.14 4ed22187defd 1f38e9ae .config console log report ci-android-414-kasan-gce-root
2018/10/17 22:51 android-4.14 6d46bcc5a747 b2695b95 .config console log report ci-android-414-kasan-gce-root
2018/10/03 06:26 android-4.14 ff9973a5da5e 0f3e0261 .config console log report ci-android-414-kasan-gce-root
2018/09/29 17:46 android-4.14 84ae3e35e1ce 41e4b329 .config console log report ci-android-414-kasan-gce-root
* Struck through repros no longer work on HEAD.