INFO: task syz-executor.5:7967 blocked for more than 140 seconds. Not tainted 4.9.194+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29784 7967 4574 0x00000004 0000000000000087 ffff8801a14f17c0 ffff8801c4beee00 ffff8801db621000 ffff88019fac5f00 ffff8801db621018 ffff8801a0fd7b68 ffffffff8281af8e 0000000000000000 0000000000000000 000000000000004c ffff8801db6218f0 Call Trace: [<000000006364a214>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<0000000080cc6f98>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<000000000fb728c7>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<000000000fb728c7>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000417b98d9>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987 [<00000000a0a464a9>] vfs_ioctl fs/ioctl.c:43 [inline] [<00000000a0a464a9>] file_ioctl fs/ioctl.c:493 [inline] [<00000000a0a464a9>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 [<000000007f5c3905>] SYSC_ioctl fs/ioctl.c:694 [inline] [<000000007f5c3905>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 [<000000008efa78b3>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<000000004868e485>] 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: [<00000000e6563352>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<00000000e6563352>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<000000007443623d>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336 1 lock held by rsyslogd/1891: #0: (&f->f_pos_lock){+.+.+.}, at: [<0000000098599cb3>] __fdget_pos+0xa8/0xd0 fs/file.c:782 2 locks held by getty/2019: #0: (&tty->ldisc_sem){++++++}, at: [<000000009a65ad2c>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+...}, at: [<00000000aac7a7f2>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.5/7967: #0: (loop_index_mutex){+.+.+.}, at: [<000000004ae9a93b>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973 #1: (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<00000000417b98d9>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987 2 locks held by syz-executor.4/7965: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<00000000708b099f>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000159967aa>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 1 lock held by syz-executor.4/7972: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b22c2bdb>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by blkid/7961: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000e7500f00>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000e4928744>] lo_release+0x20/0x1b0 drivers/block/loop.c:1663 2 locks held by syz-executor.2/7966: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<00000000708b099f>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000159967aa>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by blkid/7968: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b22c2bdb>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000efcbd70e>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 1 lock held by syz-executor.3/7974: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b22c2bdb>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 1 lock held by syz-executor.3/7996: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b22c2bdb>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by blkid/7973: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b22c2bdb>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000efcbd70e>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0 ffff8801d98d7cc8 ffffffff81b67001 0000000000000001 0000000000000000 0000000000000001 ffffffff81099d01 dffffc0000000000 ffff8801d98d7d00 ffffffff81b7229c 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<00000000d2a9ef8b>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000d2a9ef8b>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000769f481f>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<000000009e95a6cb>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<000000006287734f>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<000000008c18de70>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<000000008c18de70>] check_hung_task kernel/hung_task.c:126 [inline] [<000000008c18de70>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<000000008c18de70>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<000000004e8c4bdf>] kthread+0x278/0x310 kernel/kthread.c:211 [<0000000031eb8ca5>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff8282a0e1