Unable to find swap-space signature INFO: task syz-executor.3:5272 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.3 D24808 5272 24434 0x00000006 ffff8801c4304740 0000000000000000 ffff8801db621000 ffffffff83031180 ffff8801db621018 ffff8801ca027838 ffffffff82801a4e 0000000000000000 ffff8801ca0277b0 00ffffff81bb61ac ffff8801db6218f0 1ffff10039404ef6 Call Trace: [<00000000f52ce8d4>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000c1367c9d>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000c4336c32>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000c4336c32>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000e5493bc1>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 [<000000000f07f385>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606 [<000000009e6b3076>] blkdev_put+0x88/0x560 fs/block_dev.c:1671 [<0000000002f94184>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678 [<00000000b0db6f9a>] __fput+0x274/0x720 fs/file_table.c:208 [<000000009bf96555>] ____fput+0x16/0x20 fs/file_table.c:244 [<00000000883403c2>] task_work_run+0x108/0x180 kernel/task_work.c:116 [<00000000e7aae94c>] get_signal+0x1643/0x1aa0 kernel/signal.c:2193 [<000000000a645f84>] do_signal+0x9c/0x1920 arch/x86/kernel/signal.c:807 [<00000000b25de361>] exit_to_usermode_loop+0x11c/0x160 arch/x86/entry/common.c:158 [<00000000613e28cb>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] [<00000000613e28cb>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline] [<00000000613e28cb>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290 [<00000000b5aa26ba>] 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: [<000000002b517d69>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<000000002b517d69>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<00000000a1082e5b>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 1 lock held by rsyslogd/1911: #0: (&f->f_pos_lock){+.+.+.}, at: [<000000006fb98186>] __fdget_pos+0xa8/0xd0 fs/file.c:782 2 locks held by getty/2039: #0: (&tty->ldisc_sem){++++++}, at: [<000000007213b10f>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [<000000002bbc554a>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/5272: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000675fa5c8>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000e5493bc1>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 3 locks held by syz-executor.4/5315: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000675fa5c8>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000e5493bc1>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000053cfdcf5>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000053cfdcf5>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 1 lock held by syz-executor.4/5323: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000007f395fa>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by syz-executor.1/5316: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<00000000978997a9>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d396afc1>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 1 lock held by syz-executor.1/5325: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000007f395fa>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 1 lock held by blkid/5321: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000007f395fa>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by blkid/5324: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000007f395fa>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000026c4108b>] 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: [<000000005f5b83e3>] __dump_stack lib/dump_stack.c:15 [inline] [<000000005f5b83e3>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<0000000096401eec>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000f4ebb9bd>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<00000000f2198686>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000d97d34e2>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000d97d34e2>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000d97d34e2>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000d97d34e2>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<00000000221e98b5>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000c3ce473f>] 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