INFO: task syz-executor.0:18511 blocked for more than 140 seconds. Not tainted 4.9.170+ #48 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D27656 18511 18216 0x00000004 ffff8801a4552f80 0000000000000000 ffff8801db621000 ffffffff83031180 ffff8801db621018 ffff8801a3dd77c8 ffffffff82801a4e ffff8801a4552f80 dffffc0000000000 00ff8801a4552f80 ffff8801db6218f0 1ffff100347baee8 Call Trace: [<00000000fd2ea6d2>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<000000006b28d3bf>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<000000004633a660>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<000000004633a660>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000a5b15fba>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 [<000000001dc01281>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:638 [<00000000b047f3c8>] loop_set_status+0xc02/0x1260 drivers/block/loop.c:1197 [<0000000067b91265>] loop_set_status64+0xd7/0x130 drivers/block/loop.c:1306 [<000000001bc8a335>] lo_ioctl+0x4b8/0x1a10 drivers/block/loop.c:1431 [<000000006f181f72>] __blkdev_driver_ioctl block/ioctl.c:294 [inline] [<000000006f181f72>] blkdev_ioctl+0xe14/0x19e0 block/ioctl.c:590 [<0000000014d31e1f>] block_ioctl+0xde/0x120 fs/block_dev.c:1696 [<00000000a5a92c93>] vfs_ioctl fs/ioctl.c:43 [inline] [<00000000a5a92c93>] file_ioctl fs/ioctl.c:493 [inline] [<00000000a5a92c93>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 [<000000007453c95a>] SYSC_ioctl fs/ioctl.c:694 [inline] [<000000007453c95a>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 [<000000002cb8d455>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [<00000000e03b7c31>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/24: #0: (rcu_read_lock){......}, at: [<000000002ce9af30>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<000000002ce9af30>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<00000000aa9853cf>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 1 lock held by rsyslogd/1897: #0: (&f->f_pos_lock){+.+.+.}, at: [<000000006909d110>] __fdget_pos+0xa8/0xd0 fs/file.c:782 2 locks held by getty/2024: #0: (&tty->ldisc_sem){++++++}, at: [<00000000df006f25>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [<000000008e87d5c4>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.5/5620: #0: (&tty->ldisc_sem){++++++}, at: [<00000000df006f25>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [<000000008e87d5c4>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/18511: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<00000000d7067065>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a5b15fba>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 1 lock held by syz-executor.1/18512: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000008737721a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 3 locks held by blkid/18510: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000e2758781>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000b02f43d9>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000029553256>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000029553256>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by blkid/18514: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000008737721a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000d959fbaf>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.170+ #48 ffff8801d98d7cc8 ffffffff81b4fb21 0000000000000001 0000000000000000 0000000000000001 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5adbc 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<00000000405d6174>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000405d6174>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000f47c891a>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<000000004e988c5d>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<0000000098605108>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000a6ff337f>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000a6ff337f>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000a6ff337f>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000a6ff337f>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<0000000032b91055>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000e1182ce3>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff82810ac2