INFO: task syz-executor.5:24330 blocked for more than 140 seconds. Not tainted 4.14.184-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29248 24330 6352 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 loop_reread_partitions+0x72/0x80 drivers/block/loop.c:624 loop_set_status+0xbfd/0x11f0 drivers/block/loop.c:1193 loop_set_status64+0x92/0xe0 drivers/block/loop.c:1311 lo_ioctl+0x587/0x1c00 drivers/block/loop.c:1441 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x91d/0x17c0 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1881 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c9f7 RSP: 002b:00007ff29a2f39d8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045c9f7 RDX: 00007ff29a2f3ac0 RSI: 0000000000004c04 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000202 R12: 00000000ffffffff R13: 0000000000000c6a R14: 00000000004c1c55 R15: 00007ff29a2f46d4 INFO: task syz-executor.4:24333 blocked for more than 140 seconds. Not tainted 4.14.184-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28784 24333 6356 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x15b/0x2d0 drivers/block/loop.c:2007 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45cb29 RSP: 002b:00007f5b9cb8cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e96a0 RCX: 000000000045cb29 RDX: 0000000000000005 RSI: 0000000000004c81 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000401 R14: 00000000004c6c83 R15: 00007f5b9cb8d6d4 INFO: task systemd-udevd:24336 blocked for more than 140 seconds. Not tainted 4.14.184-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D28832 24336 3638 0x00000104 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1634 __blkdev_get+0xa70/0x10c0 fs/block_dev.c:1537 blkdev_get+0x84/0x8a0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb68/0x2aa0 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x292/0x3e0 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f1dd579d840 RSP: 002b:00007ffee8040f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000055ae499f0d90 RCX: 00007f1dd579d840 RDX: 000055ae48bfafe3 RSI: 00000000000a0800 RDI: 000055ae499eec80 RBP: 00007ffee80410e0 R08: 000055ae48bfa670 R09: 0000000000000010 R10: 000055ae48bfad0c R11: 0000000000000246 R12: 00007ffee8041030 R13: 000055ae499f16c0 R14: 0000000000000003 R15: 000000000000000e Showing all locks held in the system: 1 lock held by khungtaskd/1052: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by syz-executor.5/24330: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x87/0x1c00 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 2 locks held by syz-executor.4/24333: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x61/0x2d0 drivers/block/loop.c:1993 #1: (&lo->lo_ctl_mutex){+.+.}, at: [] loop_control_ioctl+0x15b/0x2d0 drivers/block/loop.c:2007 2 locks held by systemd-udevd/24336: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x192/0x10c0 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1634 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1052 Comm: khungtaskd Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3631 Comm: systemd-journal Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888094654500 task.stack: ffff888094658000 RIP: 0010:___bpf_prog_run+0x9c/0x5bd0 kernel/bpf/core.c:959 RSP: 0018:ffff88809465fa48 EFLAGS: 00000246 RAX: 00000000000000b4 RBX: dffffc0000000000 RCX: 0000000000000027 RDX: 0000000000000000 RSI: ffffc900018e6030 RDI: ffffc900018e606a RBP: ffff88809465fb58 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff868f2ee0 R13: 1ffff110128cbf50 R14: ffffed10128cbf71 R15: ffffc900018e61d8 FS: 00007f887f5308c0(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f887c9a2000 CR3: 0000000094e33000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: Code: 24 10 49 01 de e8 f5 01 f7 ff 4c 89 f8 4c 89 fa 48 c1 e8 03 83 e2 07 0f b6 04 18 38 d0 7f 08 84 c0 0f 85 01 3f 00 00 41 0f b6 07 <48> 8d 3c c5 e0 2e 8f 86 48 89 fa 48 c1 ea 03 80 3c 1a 00 0f 85