syzbot
INFO: task hung in blkdev_reread_part
Status:
public: reported C repro on 2019/04/10 16:04
Reported-by: syzbot+b779ba2bf386464eebd0@syzkaller.appspotmail.com
First crash: 2886d, last: 2436d
Sample crash report:
INFO: task syz-executor825:1893 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor825 D27408 1893 1883 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
blkdev_reread_part+0x18/0x30 block/ioctl.c:192
loop_reread_partitions+0x72/0x80 drivers/block/loop.c:614
loop_set_status+0xa84/0xf40 drivers/block/loop.c:1169
loop_set_status64+0x8d/0xe0 drivers/block/loop.c:1287
lo_ioctl+0x3cd/0x17d0 drivers/block/loop.c:1400
__blkdev_driver_ioctl block/ioctl.c:297 [inline]
blkdev_ioctl+0x57d/0x18c0 block/ioctl.c:594
block_ioctl+0xd9/0x120 fs/block_dev.c:1873
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441247
RSP: 002b:00007ffc0bb3bbf8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441247
RDX: 00007ffc0bb3bc90 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000010 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000005
R13: 0000000000000004 R14: 0000000000000004 R15: 0000000000000000
INFO: task syz-executor825:1898 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor825 D28184 1898 1884 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
blkdev_reread_part+0x18/0x30 block/ioctl.c:192
loop_reread_partitions+0x72/0x80 drivers/block/loop.c:614
loop_set_status+0xa84/0xf40 drivers/block/loop.c:1169
loop_set_status64+0x8d/0xe0 drivers/block/loop.c:1287
lo_ioctl+0x3cd/0x17d0 drivers/block/loop.c:1400
__blkdev_driver_ioctl block/ioctl.c:297 [inline]
blkdev_ioctl+0x57d/0x18c0 block/ioctl.c:594
block_ioctl+0xd9/0x120 fs/block_dev.c:1873
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441247
RSP: 002b:00007ffc0bb3bbf8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441247
RDX: 00007ffc0bb3bc90 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000010 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000005
R13: 0000000000000004 R14: 0000000000000004 R15: 0000000000000000
INFO: task syz-executor825:1903 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor825 D28360 1903 1882 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
blkdev_reread_part+0x18/0x30 block/ioctl.c:192
loop_reread_partitions+0x72/0x80 drivers/block/loop.c:614
loop_set_status+0xa84/0xf40 drivers/block/loop.c:1169
loop_set_status64+0x8d/0xe0 drivers/block/loop.c:1287
lo_ioctl+0x3cd/0x17d0 drivers/block/loop.c:1400
__blkdev_driver_ioctl block/ioctl.c:297 [inline]
blkdev_ioctl+0x57d/0x18c0 block/ioctl.c:594
block_ioctl+0xd9/0x120 fs/block_dev.c:1873
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441247
RSP: 002b:00007ffc0bb3bbf8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441247
RDX: 00007ffc0bb3bc90 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000010 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000005
R13: 0000000000000004 R14: 0000000000000004 R15: 0000000000000000
INFO: task blkid:1909 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid D28008 1909 1896 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
lo_release+0x1a/0x190 drivers/block/loop.c:1635
__blkdev_put+0x526/0x6e0 fs/block_dev.c:1783
blkdev_close+0x86/0xb0 fs/block_dev.c:1855
__fput+0x25e/0x6f0 fs/file_table.c:210
task_work_run+0x116/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x12e/0x150 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+0x35d/0x4b0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f6394d8a2b0
RSP: 002b:00007fff754db3d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6394d8a2b0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000028 R09: 0000000001680000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000016c2030
R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005
INFO: task syz-executor825:1914 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor825 D29656 1914 1885 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1951
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441339
RSP: 002b:00007ffc0bb3be38 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441339
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 000000000153e880 R11: 0000000000000213 R12: 00000000000b3358
R13: 0000000000402200 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor825:1915 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor825 D29656 1915 1887 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1951
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441339
RSP: 002b:00007ffc0bb3be38 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441339
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 000000000153e880 R11: 0000000000000213 R12: 00000000000b3355
R13: 0000000000402200 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor825:1916 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor825 D29656 1916 1886 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
loop_control_ioctl+0x180/0x310 drivers/block/loop.c:1965
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441339
RSP: 002b:00007ffc0bb3be38 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441339
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 000000000153e880 R11: 0000000000000213 R12: 00000000000b33da
R13: 0000000000402200 R14: 0000000000000000 R15: 0000000000000000
INFO: task blkid:1917 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid D27816 1917 1895 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
lo_open+0x17/0xa0 drivers/block/loop.c:1592
__blkdev_get+0x8e2/0xe50 fs/block_dev.c:1529
blkdev_get+0x97/0x8c0 fs/block_dev.c:1604
blkdev_open+0x1bd/0x240 fs/block_dev.c:1762
do_dentry_open+0x426/0xda0 fs/open.c:764
vfs_open+0x11c/0x210 fs/open.c:878
do_last fs/namei.c:3455 [inline]
path_openat+0x5f9/0x2930 fs/namei.c:3597
do_filp_open+0x197/0x270 fs/namei.c:3631
do_sys_open+0x2ef/0x580 fs/open.c:1071
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f5aa593d120
RSP: 002b:00007ffe28d6a108 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5aa593d120
RDX: 00007ffe28d6af41 RSI: 0000000000000000 RDI: 00007ffe28d6af41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000181c030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:1918 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid D29000 1918 1899 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
lo_open+0x17/0xa0 drivers/block/loop.c:1592
__blkdev_get+0x8e2/0xe50 fs/block_dev.c:1529
blkdev_get+0x97/0x8c0 fs/block_dev.c:1604
blkdev_open+0x1bd/0x240 fs/block_dev.c:1762
do_dentry_open+0x426/0xda0 fs/open.c:764
vfs_open+0x11c/0x210 fs/open.c:878
do_last fs/namei.c:3455 [inline]
path_openat+0x5f9/0x2930 fs/namei.c:3597
do_filp_open+0x197/0x270 fs/namei.c:3631
do_sys_open+0x2ef/0x580 fs/open.c:1071
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fcec469a120
RSP: 002b:00007ffddf120668 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcec469a120
RDX: 00007ffddf121f41 RSI: 0000000000000000 RDI: 00007ffddf121f41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000023f0030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:1919 blocked for more than 140 seconds.
Not tainted 4.14.88+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid D27816 1919 1892 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
lo_open+0x17/0xa0 drivers/block/loop.c:1592
__blkdev_get+0x267/0xe50 fs/block_dev.c:1467
blkdev_get+0x97/0x8c0 fs/block_dev.c:1604
blkdev_open+0x1bd/0x240 fs/block_dev.c:1762
do_dentry_open+0x426/0xda0 fs/open.c:764
vfs_open+0x11c/0x210 fs/open.c:878
do_last fs/namei.c:3455 [inline]
path_openat+0x5f9/0x2930 fs/namei.c:3597
do_filp_open+0x197/0x270 fs/namei.c:3631
do_sys_open+0x2ef/0x580 fs/open.c:1071
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f558d692120
RSP: 002b:00007ffddd4e7b08 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f558d692120
RDX: 00007ffddd4e9f41 RSI: 0000000000000000 RDI: 00007ffddd4e9f41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000b78030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
Showing all locks held in the system:
1 lock held by khungtaskd/23:
#0: (tasklist_lock){.+.+}, at: [<ffffffffa2e04947>] debug_show_all_locks+0x74/0x20f kernel/locking/lockdep.c:4541
1 lock held by rsyslogd/1624:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffffa31c0e92>] __fdget_pos+0xa2/0xc0 fs/file.c:768
2 locks held by getty/1752:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffffa3940870>] tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffffa393bccf>] n_tty_read+0x1ff/0x1700 drivers/tty/n_tty.c:2156
2 locks held by syz-executor825/1893:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffffa39eff95>] lo_ioctl+0x85/0x17d0 drivers/block/loop.c:1373
#1: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa37215a8>] blkdev_reread_part+0x18/0x30 block/ioctl.c:192
2 locks held by syz-executor825/1898:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffffa39eff95>] lo_ioctl+0x85/0x17d0 drivers/block/loop.c:1373
#1: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa37215a8>] blkdev_reread_part+0x18/0x30 block/ioctl.c:192
2 locks held by syz-executor825/1903:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffffa39eff95>] lo_ioctl+0x85/0x17d0 drivers/block/loop.c:1373
#1: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa37215a8>] blkdev_reread_part+0x18/0x30 block/ioctl.c:192
2 locks held by blkid/1909:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa321c681>] __blkdev_put+0xb1/0x6e0 fs/block_dev.c:1770
#1: (loop_index_mutex){+.+.}, at: [<ffffffffa39f182a>] lo_release+0x1a/0x190 drivers/block/loop.c:1635
1 lock held by syz-executor825/1914:
#0: (loop_index_mutex){+.+.}, at: [<ffffffffa39f2d01>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1951
1 lock held by syz-executor825/1915:
#0: (loop_index_mutex){+.+.}, at: [<ffffffffa39f2d01>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1951
2 locks held by syz-executor825/1916:
#0: (loop_index_mutex){+.+.}, at: [<ffffffffa39f2d01>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1951
#1: (&lo->lo_ctl_mutex#2){+.+.}, at: [<ffffffffa39f2e10>] loop_control_ioctl+0x180/0x310 drivers/block/loop.c:1965
2 locks held by blkid/1917:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa321cda3>] __blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
#1: (loop_index_mutex){+.+.}, at: [<ffffffffa39eb7c7>] lo_open+0x17/0xa0 drivers/block/loop.c:1592
2 locks held by blkid/1918:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa321cda3>] __blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
#1: (loop_index_mutex){+.+.}, at: [<ffffffffa39eb7c7>] lo_open+0x17/0xa0 drivers/block/loop.c:1592
2 locks held by blkid/1919:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa321cda3>] __blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
#1: (loop_index_mutex){+.+.}, at: [<ffffffffa39eb7c7>] lo_open+0x17/0xa0 drivers/block/loop.c:1592
2 locks held by blkid/1920:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa321cda3>] __blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
#1: (loop_index_mutex){+.+.}, at: [<ffffffffa39eb7c7>] lo_open+0x17/0xa0 drivers/block/loop.c:1592
2 locks held by blkid/1922:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffffa321cda3>] __blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
#1: (loop_index_mutex){+.+.}, at: [<ffffffffa39eb7c7>] lo_open+0x17/0xa0 drivers/block/loop.c:1592
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.88+ #23
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xb9/0x11b lib/dump_stack.c:53
nmi_cpu_backtrace.cold.0+0x47/0x85 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x121/0x146 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline]
watchdog+0x574/0xa70 kernel/hung_task.c:252
kthread+0x348/0x420 kernel/kthread.c:232
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.88+ #23
task: ffffffffa5031200 task.stack: ffffffffa5000000
RIP: 0010:__local_bh_disable_ip+0x0/0xc0 kernel/softirq.c:111
RSP: 0018:ffff8881dba07fb0 EFLAGS: 00000046
RAX: 0000000080000001 RBX: ffffffffa5031200 RCX: 1ffffffff49d5884
RDX: 0000000000000000 RSI: 0000000000000200 RDI: ffffffffa2cec5ea
RBP: ffff8881dba07fe8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 000000000002a200
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881dba00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000108a3e0 CR3: 0000000169226003 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
local_bh_disable include/linux/bottom_half.h:19 [inline]
irq_enter+0xab/0xd0 kernel/softirq.c:348
scheduler_ipi+0xb6/0x340 kernel/sched/core.c:1812
reschedule_interrupt+0x84/0x90 arch/x86/entry/entry_64.S:811
</IRQ>
RIP: 0010:native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:58
RSP: 0018:ffffffffa5007d28 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff02
RAX: 0000000000000007 RBX: ffffffffa542f968 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffffa5031a2c
RBP: ffffffffa5439da8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 1ffffffff4a00fae R14: 0000000000000000 R15: ffffffffa5439e64
arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
default_idle+0x50/0x380 arch/x86/kernel/process.c:564
cpuidle_idle_call kernel/sched/idle.c:159 [inline]
do_idle+0x2da/0x3b0 kernel/sched/idle.c:268
cpu_startup_entry+0xc9/0xe0 kernel/sched/idle.c:374
start_kernel+0x701/0x73f init/main.c:710
secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240
Code: 89 04 24 e8 f3 29 44 00 48 8b 04 24 eb bd 48 89 14 24 e8 f4 29 44 00 48 8b 14 24 e9 1a ff ff ff 90 66 2e 0f 1f 84 00 00 00 00 00 <55> 53 89 f3 65 8b 05 a5 1f 33 5d a9 00 00 0f 00 0f 85 98 00 00
Struck through repros no longer work on HEAD.