syzbot


INFO: task hung in __blkdev_get

Status: upstream: reported C repro on 2019/04/11 13:17
Reported-by: syzbot+0d4351f3b3165ccaee9e@syzkaller.appspotmail.com
First crash: 1263d, last: 5d13h
similar bugs (9):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 INFO: task hung in __blkdev_get C 1504 1030d 1263d 0/3 public: reported C repro on 2019/04/12 00:00
android-44 INFO: task hung in __blkdev_get syz 521 1033d 1261d 0/2 public: reported syz repro on 2019/04/14 00:02
android-414 INFO: task hung in __blkdev_get 1859 1030d 1262d 0/1 auto-closed as invalid on 2020/02/28 16:13
upstream INFO: task hung in __blkdev_get (3) 1 1256d 1256d 0/24 closed as invalid on 2019/05/08 13:05
upstream INFO: task hung in __blkdev_get (2) 11 1354d 1478d 0/24 closed as dup on 2018/09/08 15:48
upstream INFO: task hung in __blkdev_get C 662 1626d 1751d 6/24 fixed on 2018/05/08 18:30
linux-4.19 INFO: task hung in __blkdev_get C error 117 4d21h 1140d 0/1 upstream: reported C repro on 2019/08/13 00:10
upstream INFO: task hung in __blkdev_get (4) 1 1075d 1075d 0/24 auto-closed as invalid on 2020/01/15 05:33
upstream INFO: task hung in __blkdev_get (5) 8 653d 868d 0/24 auto-closed as invalid on 2021/03/11 14:46

Sample crash report:
INFO: task systemd-udevd:4633 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
systemd-udevd   D25760  4633      1 0x00000304
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 __blkdev_get+0x191/0x1090 fs/block_dev.c:1455
 blkdev_get+0x88/0x890 fs/block_dev.c:1611
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
 do_dentry_open+0x44b/0xec0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0x628/0x2970 fs/namei.c:3569
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40f2875840
RSP: 002b:00007ffeff1d9ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffeff1d9b50 RCX: 00007f40f2875840
RDX: 000055605b6eefe3 RSI: 00000000000a0800 RDI: 000055605d081e70
RBP: 00007ffeff1da000 R08: 000055605b6ee670 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffeff1d9c60
R13: 000055605cef8010 R14: 000055605d0a8450 R15: 00007ffeff1d9b30
INFO: task systemd-udevd:8000 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
systemd-udevd   D28456  8000   4633 0x00000300
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1634
 __blkdev_get+0x306/0x1090 fs/block_dev.c:1470
 blkdev_get+0x88/0x890 fs/block_dev.c:1611
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
 do_dentry_open+0x44b/0xec0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0x628/0x2970 fs/namei.c:3569
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40f2875840
RSP: 002b:00007ffeff1d93f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000055605cefb120 RCX: 00007f40f2875840
RDX: 000055605b6eefe3 RSI: 00000000000a0800 RDI: 000055605cf0df40
RBP: 00007ffeff1d9570 R08: 000055605b6ee670 R09: 0000000000000010
R10: 000055605b6eed0c R11: 0000000000000246 R12: 00007ffeff1d94c0
R13: 000055605cefb4c0 R14: 0000000000000003 R15: 000000000000000e
INFO: task systemd-udevd:8002 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
systemd-udevd   D28712  8002   4633 0x00000300
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1634
 __blkdev_get+0x306/0x1090 fs/block_dev.c:1470
 blkdev_get+0x88/0x890 fs/block_dev.c:1611
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
 do_dentry_open+0x44b/0xec0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0x628/0x2970 fs/namei.c:3569
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40f2875840
RSP: 002b:00007ffeff1d99e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000055605cf0dc80 RCX: 00007f40f2875840
RDX: 000055605b6eefe3 RSI: 00000000000a0800 RDI: 000055605cf0de10
RBP: 00007ffeff1d9b60 R08: 000055605b6ee670 R09: 0000000000000010
R10: 000055605b6eed0c R11: 0000000000000246 R12: 00007ffeff1d9ab0
R13: 000055605cf0a880 R14: 0000000000000003 R15: 000000000000000e
INFO: task systemd-udevd:8028 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
systemd-udevd   D28416  8028   4633 0x00000300
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1634
 __blkdev_get+0xa8c/0x1090 fs/block_dev.c:1537
 blkdev_get+0x88/0x890 fs/block_dev.c:1611
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
 do_dentry_open+0x44b/0xec0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0x628/0x2970 fs/namei.c:3569
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40f2875840
RSP: 002b:00007ffeff1d93f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000055605cf0c160 RCX: 00007f40f2875840
RDX: 000055605b6eefe3 RSI: 00000000000a0800 RDI: 000055605cef99b0
RBP: 00007ffeff1d9570 R08: 000055605b6ee670 R09: 0000000000000010
R10: 000055605b6eed0c R11: 0000000000000246 R12: 00007ffeff1d94c0
R13: 000055605cf0cab0 R14: 0000000000000003 R15: 000000000000000e
INFO: task systemd-udevd:8052 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
systemd-udevd   D28616  8052   4633 0x00000300
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1634
 __blkdev_get+0xa8c/0x1090 fs/block_dev.c:1537
 blkdev_get+0x88/0x890 fs/block_dev.c:1611
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
 do_dentry_open+0x44b/0xec0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0x628/0x2970 fs/namei.c:3569
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40f2875840
RSP: 002b:00007ffeff1d93f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000055605cf0c160 RCX: 00007f40f2875840
RDX: 000055605b6eefe3 RSI: 00000000000a0800 RDI: 000055605cef8e00
RBP: 00007ffeff1d9570 R08: 000055605b6ee670 R09: 0000000000000010
R10: 000055605b6eed0c R11: 0000000000000246 R12: 00007ffeff1d94c0
R13: 000055605cf076e0 R14: 0000000000000003 R15: 000000000000000e
INFO: task systemd-udevd:8053 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
systemd-udevd   D28400  8053   4633 0x00000300
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 lo_release+0x1b/0x190 drivers/block/loop.c:1677
 __blkdev_put+0x5aa/0x800 fs/block_dev.c:1803
 blkdev_close+0x86/0xb0 fs/block_dev.c:1875
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 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+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40f2875270
RSP: 002b:00007ffeff1d4b98 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000000000f RCX: 00007f40f2875270
RDX: 00007f40f285fb58 RSI: 0000000000000000 RDI: 000000000000000f
RBP: 00007f40f372f710 R08: f29b65068fae577f R09: 0000000000000009
R10: 347260abbefa549c R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000000000 R14: 000055605cf076e0 R15: 000000000000000f
INFO: task systemd-udevd:8065 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
systemd-udevd   D27936  8065   4633 0x00000300
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1634
 __blkdev_get+0x306/0x1090 fs/block_dev.c:1470
 blkdev_get+0x88/0x890 fs/block_dev.c:1611
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772
 do_dentry_open+0x44b/0xec0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0x628/0x2970 fs/namei.c:3569
 do_filp_open+0x179/0x3c0 fs/namei.c:3603
 do_sys_open+0x296/0x410 fs/open.c:1081
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f40f2875840
RSP: 002b:00007ffeff1d93f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000055605cf076e0 RCX: 00007f40f2875840
RDX: 000055605b6eefe3 RSI: 00000000000a0800 RDI: 000055605cef99b0
RBP: 00007ffeff1d9570 R08: 000055605b6ee670 R09: 0000000000000010
R10: 000055605b6eed0c R11: 0000000000000246 R12: 00007ffeff1d94c0
R13: 000055605cf0a880 R14: 0000000000000003 R15: 000000000000000e
INFO: task syz-executor282:11533 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor282 D28912 11533   7993 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions drivers/block/loop.c:624 [inline]
 loop_clr_fd+0x9ca/0xc20 drivers/block/loop.c:1078
 lo_ioctl+0x895/0x1cd0 drivers/block/loop.c:1424
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x540/0x1830 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1893
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f49efe45027
RSP: 002b:00007ffc55f32a08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffc55f32a30 RCX: 00007f49efe45027
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000005
RBP: 0000000000000005 R08: 0000000000000001 R09: 00007ffc55f328a0
R10: 00007ffc55f32757 R11: 0000000000000246 R12: 0000000000000004
R13: 0000555556f212c0 R14: 00007ffc55f32ab0 R15: 0000000000000008
INFO: task syz-executor282:11535 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor282 D28720 11535   7995 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions drivers/block/loop.c:624 [inline]
 loop_clr_fd+0x9ca/0xc20 drivers/block/loop.c:1078
 lo_ioctl+0x895/0x1cd0 drivers/block/loop.c:1424
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x540/0x1830 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1893
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f49efe45027
RSP: 002b:00007ffc55f32a08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffc55f32a30 RCX: 00007f49efe45027
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000005
RBP: 0000000000000005 R08: 0000000000000001 R09: 00007ffc55f328a0
R10: 00007ffc55f32757 R11: 0000000000000246 R12: 0000000000000004
R13: 0000555556f212c0 R14: 00007ffc55f32ab0 R15: 0000000000000008
INFO: task syz-executor282:11556 blocked for more than 140 seconds.
      Not tainted 4.14.290-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor282 D28912 11556   7998 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 loop_control_ioctl+0x181/0x3f0 drivers/block/loop.c:2007
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f49efe45179
RSP: 002b:00007ffc55f32c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f49efe45179
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
R10: 00007ffc55f326e0 R11: 0000000000000246 R12: 0000000000099b07
R13: 00007ffc55f32c90 R14: 00007ffc55f32c7c R15: 00007ffc55f32c80

Showing all locks held in the system:
1 lock held by khungtaskd/1533:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8701eaf9>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
1 lock held by systemd-udevd/4633:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff81941cd1>] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455
2 locks held by systemd-udevd/8000:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff81941cd1>] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff838cc8e9>] lo_open+0x19/0xb0 drivers/block/loop.c:1634
2 locks held by systemd-udevd/8002:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff81941cd1>] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff838cc8e9>] lo_open+0x19/0xb0 drivers/block/loop.c:1634
2 locks held by systemd-udevd/8028:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff81941cd1>] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff838cc8e9>] lo_open+0x19/0xb0 drivers/block/loop.c:1634
2 locks held by systemd-udevd/8052:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff81941cd1>] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff838cc8e9>] lo_open+0x19/0xb0 drivers/block/loop.c:1634
2 locks held by systemd-udevd/8053:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff81940048>] __blkdev_put+0xd8/0x800 fs/block_dev.c:1790
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff838d473b>] lo_release+0x1b/0x190 drivers/block/loop.c:1677
2 locks held by systemd-udevd/8065:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff81941cd1>] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff838cc8e9>] lo_open+0x19/0xb0 drivers/block/loop.c:1634
2 locks held by syz-executor282/11533:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff838d5f97>] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff830bd23b>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by syz-executor282/11535:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff838d5f97>] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff830bd23b>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by syz-executor282/11556:
 #0:  (loop_index_mutex){+.+.}, at: [<ffffffff838d3047>] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993
 #1:  (&lo->lo_ctl_mutex){+.+.}, at: [<ffffffff838d3161>] loop_control_ioctl+0x181/0x3f0 drivers/block/loop.c:2007
2 locks held by syz-executor282/11557:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff838d5f97>] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff830bd23b>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
1 lock held by syz-executor282/11559:
 #0:  (loop_index_mutex){+.+.}, at: [<ffffffff838d3047>] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993
1 lock held by syz-executor282/11562:
 #0:  (loop_index_mutex){+.+.}, at: [<ffffffff838d3047>] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993

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

NMI backtrace for cpu 1
CPU: 1 PID: 1533 Comm: khungtaskd Not tainted 4.14.290-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x180 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+0x5b9/0xb40 kernel/hung_task.c:274
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff8723f20e

Fix bisection attempts:
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2021/11/29 23:09 linux-4.14.y 66722c42ec91 d5a3ae1f .config log report syz C
ci2-linux-4-14 2021/10/30 22:18 linux-4.14.y cd5296934610 d5a3ae1f .config log report syz C
ci2-linux-4-14 2021/08/01 13:29 linux-4.14.y ce4d1565392b d5a3ae1f .config log report syz C
ci2-linux-4-14 2021/06/16 23:07 linux-4.14.y cfb41ef9deb1 d5a3ae1f .config log report syz C
* Struck through repros no longer work on HEAD.
Crashes (729):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2022/07/30 21:03 linux-4.14.y b641242202ed fef302b1 .config log report syz C INFO: task hung in __blkdev_get
ci2-linux-4-14 2020/08/31 01:03 linux-4.14.y d7e78d08fa77 d5a3ae1f .config log report syz C
ci2-linux-4-14 2020/07/04 11:02 linux-4.14.y b850307b279c 51095195 .config log report syz C
ci2-linux-4-14 2019/04/29 03:51 linux-4.14.y fa5941f45d7e b617407b .config log report syz
ci2-linux-4-14 2022/09/20 20:57 linux-4.14.y 4edbf74132a4 c4b8ccfd .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/09/20 11:23 linux-4.14.y 4edbf74132a4 7c41a9ba .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/09/20 08:45 linux-4.14.y 5df8b4735177 7c41a9ba .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/09/16 19:08 linux-4.14.y 5df8b4735177 dd9a85ff .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/09/08 21:20 linux-4.14.y 65640c873dcf f3027468 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/09/04 02:13 linux-4.14.y e548869f356f 28811d0a .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/08/29 16:46 linux-4.14.y e548869f356f d7593c58 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/08/22 03:24 linux-4.14.y b641242202ed 26a13b38 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/08/11 13:49 linux-4.14.y b641242202ed 787ed7e0 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/20 14:46 linux-4.14.y 424a46ea058e 88cb1383 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/19 10:18 linux-4.14.y 424a46ea058e 72a3cc0c .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/15 12:21 linux-4.14.y 424a46ea058e 5d921b08 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/10 19:44 linux-4.14.y 1048779a1d7d b5765a15 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/07 17:52 linux-4.14.y 1048779a1d7d bff65f44 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/07 16:03 linux-4.14.y 1048779a1d7d bff65f44 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/07 05:11 linux-4.14.y ed2e96e11936 bff65f44 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/06 18:37 linux-4.14.y ed2e96e11936 bff65f44 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/02 15:46 linux-4.14.y ed2e96e11936 1434eec0 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/07/02 00:24 linux-4.14.y f051383ef03b 1434eec0 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/06/28 03:12 linux-4.14.y f051383ef03b ef82eb2c .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/06/26 20:39 linux-4.14.y f051383ef03b a371c43c .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/06/21 06:23 linux-4.14.y 84bae26850e3 0fc5c330 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/06/18 15:42 linux-4.14.y 84bae26850e3 8f633d84 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/06/08 21:37 linux-4.14.y b8f3be299d51 0d5abf15 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/06/03 01:02 linux-4.14.y 501eec4f9e13 02dddea8 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/06/01 21:33 linux-4.14.y 501eec4f9e13 b4bc6a3d .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/31 17:08 linux-4.14.y 501eec4f9e13 af70c3a9 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/27 23:03 linux-4.14.y 501eec4f9e13 a46af346 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/25 13:37 linux-4.14.y 501eec4f9e13 3037caa9 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/21 17:10 linux-4.14.y dffb5c6ff09c 7268fa62 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/18 15:23 linux-4.14.y dffb5c6ff09c 50c53f39 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/18 09:14 linux-4.14.y dffb5c6ff09c 744a39e2 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/14 09:53 linux-4.14.y 569d1abf9402 744a39e2 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/11 20:51 linux-4.14.y e3a56aaade89 beb0b407 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/11 19:31 linux-4.14.y e3a56aaade89 beb0b407 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/09 08:40 linux-4.14.y e3a56aaade89 e60b1103 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/05/04 09:40 linux-4.14.y e3a56aaade89 dc9e5259 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/04/29 14:47 linux-4.14.y e3a56aaade89 44a5ca63 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/04/28 02:13 linux-4.14.y e3a56aaade89 8a1f1f07 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/04/22 05:12 linux-4.14.y 15a1c6b6f516 2738b391 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/04/21 15:40 linux-4.14.y 15a1c6b6f516 2738b391 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/04/15 23:29 linux-4.14.y 74766a973637 8bcc32a6 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/04/12 21:10 linux-4.14.y 74766a973637 dacb3f1c .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/03/31 11:30 linux-4.14.y af1af6ebca0e c4c32d8c .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/03/23 09:02 linux-4.14.y 004bfaafc45c 5ff41e94 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/03/17 03:37 linux-4.14.y eb045674aab3 dfa9a8ed .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/02/28 06:01 linux-4.14.y fa33f9094f36 45a13a73 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/02/01 23:27 linux-4.14.y b86ee2b7ae42 4ebb2798 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2022/01/18 08:05 linux-4.14.y 4ba8e26127c3 731a2d23 .config log report info INFO: task hung in __blkdev_get
ci2-linux-4-14 2021/01/17 11:46 linux-4.14.y f79dc86058bc 813be542 .config log report info
ci2-linux-4-14 2019/04/11 12:16 linux-4.14.y 1ec8f1f0bffe e955ac50 .config log report
* Struck through repros no longer work on HEAD.