INFO: task syz-executor.4:16474 blocked for more than 140 seconds. kobject: 'loop5' (00000000dcf7694b): kobject_uevent_env Not tainted 5.0.0+ #6 kobject: 'loop5' (00000000dcf7694b): fill_kobj_path: path = '/devices/virtual/block/loop5' "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29312 16474 8006 0x00000000 Call Trace: context_switch kernel/sched/core.c:2844 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3485 kobject: 'kvm' (000000009522c22d): kobject_uevent_env kobject: 'loop4' (00000000985087ab): kobject_uevent_env kobject: 'loop4' (00000000985087ab): fill_kobj_path: path = '/devices/virtual/block/loop4' kobject: 'kvm' (000000009522c22d): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'loop3' (000000009ff2806d): kobject_uevent_env kobject: 'loop2' (00000000e18b3a81): kobject_uevent_env schedule+0x92/0x180 kernel/sched/core.c:3529 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3587 kobject: 'loop2' (00000000e18b3a81): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'loop3' (000000009ff2806d): fill_kobj_path: path = '/devices/virtual/block/loop3' __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 kobject: 'loop1' (0000000073c8def0): kobject_uevent_env kobject: 'loop1' (0000000073c8def0): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'kvm' (000000009522c22d): kobject_uevent_env mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 kobject: 'kvm' (000000009522c22d): fill_kobj_path: path = '/devices/virtual/misc/kvm' mon_bin_read+0x60/0x640 drivers/usb/mon/mon_bin.c:813 kobject: 'loop0' (00000000e9d4fa0b): kobject_uevent_env do_loop_readv_writev fs/read_write.c:700 [inline] do_loop_readv_writev fs/read_write.c:687 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:921 kobject: 'loop0' (00000000e9d4fa0b): fill_kobj_path: path = '/devices/virtual/block/loop0' vfs_readv+0xf0/0x160 fs/read_write.c:983 do_preadv+0x1c4/0x280 fs/read_write.c:1067 __do_sys_preadv fs/read_write.c:1117 [inline] __se_sys_preadv fs/read_write.c:1112 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1112 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e29 Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc34c7ccc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457e29 RDX: 0000000000000001 RSI: 0000000020000480 RDI: 0000000000000004 RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc34c7cd6d4 R13: 00000000004c4933 R14: 00000000004d8210 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1039: #0: 000000005c66a1f1 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4389 1 lock held by rsyslogd/7831: 2 locks held by getty/7953: #0: 00000000676c5c32 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a7cd07ae (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7954: #0: 0000000090305b6e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a641a400 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7955: #0: 0000000014eac60a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000080749c8c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7956: #0: 0000000015f0fa8a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000c0673ded (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7957: #0: 000000004f7463c0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a5f7f59b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7958: #0: 0000000049478730 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000003b298995 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 2 locks held by getty/7959: #0: 0000000039727ba0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000069abd528 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2154 1 lock held by syz-executor.0/7992: #0: 00000000ef7e58ff (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 2 locks held by syz-executor.1/7995: #0: 00000000255e055c (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 #1: 00000000974de284 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1722 1 lock held by syz-executor.3/8002: #0: 0000000065f36edc (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 2 locks held by syz-executor.4/8006: #0: 00000000f9f9308c (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 #1: 00000000974de284 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1722 2 locks held by syz-executor.5/8008: #0: 000000005ceee1f1 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 #1: 00000000974de284 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1722 1 lock held by syz-executor.4/16439: #0: 000000005c1af97a (&rp->fetch_lock){+.+.}, at: mon_bin_read+0x60/0x640 drivers/usb/mon/mon_bin.c:813 1 lock held by syz-executor.4/16474: #0: 000000005c1af97a (&rp->fetch_lock){+.+.}, at: mon_bin_read+0x60/0x640 drivers/usb/mon/mon_bin.c:813 1 lock held by syz-executor.2/23471: #0: 00000000974de284 (loop_ctl_mutex){+.+.}, at: __loop_clr_fd+0x88/0xc90 drivers/block/loop.c:1046 2 locks held by blkid/23482: #0: 0000000065f36edc (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 #1: 00000000974de284 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1722 2 locks held by blkid/23483: #0: 00000000ae549d31 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 #1: 00000000974de284 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1722 2 locks held by blkid/23484: #0: 00000000ef7e58ff (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 #1: 00000000974de284 (loop_ctl_mutex){+.+.}, at: lo_open+0x1d/0xd0 drivers/block/loop.c:1722 1 lock held by blkid/23485: #0: 00000000255e055c (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1494 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1039 Comm: khungtaskd Not tainted 5.0.0+ #6 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x9df/0xee0 kernel/hung_task.c:287 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:57 kobject: 'loop2' (00000000e18b3a81): kobject_uevent_env