INFO: task syz-executor.0:22392 blocked for more than 140 seconds. Not tainted 4.14.273-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28872 22392 7978 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 loop_reread_partitions drivers/block/loop.c:624 [inline] loop_set_status+0xeeb/0x12b0 drivers/block/loop.c:1193 loop_set_status64+0x92/0xe0 drivers/block/loop.c:1311 lo_ioctl+0x587/0x1cd0 drivers/block/loop.c:1441 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 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: 0033:0x7f4acebebe07 RSP: 002b:00007f4acd560ed8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4acd560f20 RCX: 00007f4acebebe07 RDX: 00007f4acd561030 RSI: 0000000000004c04 RDI: 0000000000000032 RBP: 00007f4acec4608d R08: 0000000000000000 R09: ffffffff00000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f4acd561030 R13: 00007ffe5d19f6bf R14: 00007f4acd561300 R15: 0000000000022000 INFO: task syz-executor.0:22393 blocked for more than 140 seconds. Not tainted 4.14.273-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28872 22393 7978 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 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: 0033:0x7f4acebebe07 RSP: 002b:00007f4acd53fe78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4acd5406b8 RCX: 00007f4acebebe07 RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000033 RBP: 0000000000000033 R08: 0000000000000000 R09: ffffffff00000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000010 R13: 0000000000000003 R14: 0000000020000648 R15: 0000000000000003 INFO: task syz-executor.1:22400 blocked for more than 140 seconds. Not tainted 4.14.273-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28536 22400 7979 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 loop_control_ioctl+0x181/0x3f0 drivers/block/loop.c:2007 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 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: 0033:0x7f8482009049 RSP: 002b:00007f848097e168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f848211bf60 RCX: 00007f8482009049 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000004 RBP: 00007f848206308d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe2d98ff7f R14: 00007f848097e300 R15: 0000000000022000 INFO: task systemd-udevd:22407 blocked for more than 140 seconds. Not tainted 4.14.273-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D28704 22407 4626 0x00000300 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1634 __blkdev_get+0xa8c/0x1090 fs/block_dev.c:1537 blkdev_get+0x88/0x890 fs/block_dev.c:1611 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772 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+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f66cbc20840 RSP: 002b:00007ffe7b03f088 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000562b087a0f40 RCX: 00007f66cbc20840 RDX: 0000562b06f59fe3 RSI: 00000000000a0800 RDI: 0000562b087a2e90 RBP: 00007ffe7b03f200 R08: 0000562b06f59670 R09: 0000000000000010 R10: 0000562b06f59d0c R11: 0000000000000246 R12: 00007ffe7b03f150 R13: 0000562b087a0e20 R14: 0000000000000003 R15: 000000000000000e Showing all locks held in the system: 1 lock held by khungtaskd/1533: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by in:imklog/7697: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:819 2 locks held by syz-executor.0/22392: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 1 lock held by syz-executor.0/22393: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414 2 locks held by syz-executor.1/22400: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993 #1: (&lo->lo_ctl_mutex){+.+.}, at: [] loop_control_ioctl+0x181/0x3f0 drivers/block/loop.c:2007 2 locks held by systemd-udevd/22407: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1634 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1533 Comm: khungtaskd Not tainted 4.14.273-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+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 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+0x5b9/0xb40 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8 Comm: rcu_preempt Not tainted 4.14.273-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880b5420200 task.stack: ffff8880b5428000 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:trace_hardirqs_on_caller+0x354/0x580 kernel/locking/lockdep.c:2931 RSP: 0018:ffff8880b542fb10 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880b5420200 RCX: 0000000000000000 RDX: 1ffff11016a84149 RSI: 0000000000000001 RDI: ffff8880b5420a48 RBP: 00000000001aafff R08: ffffffff8bfe8348 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff8880b542fbd8 R14: ffff8880b542fd18 R15: 1ffff11016a85f6b FS: 0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fee0b583008 CR3: 0000000092912000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x79/0xe0 kernel/locking/spinlock.c:192 debug_object_assert_init lib/debugobjects.c:663 [inline] debug_object_assert_init+0x22d/0x2d0 lib/debugobjects.c:627 debug_timer_assert_init kernel/time/timer.c:708 [inline] debug_assert_init kernel/time/timer.c:756 [inline] try_to_del_timer_sync+0x5d/0xe0 kernel/time/timer.c:1176 del_timer_sync+0x17c/0x240 kernel/time/timer.c:1246 schedule_timeout+0x4b7/0xe90 kernel/time/timer.c:1748 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: ea 03 8d 68 01 48 b8 00 00 00 00 00 fc ff df 89 ab 30 08 00 00 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 26 01 00 00 89 ab 48 08 00 00 <65> 48 8b 1c 25 c0 7f 02 00 48 8d bb 84 08 00 00 48 b8 00 00 00 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 8d 68 01 lea 0x1(%rax),%ebp 3: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax a: fc ff df d: 89 ab 30 08 00 00 mov %ebp,0x830(%rbx) 13: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax 17: 84 c0 test %al,%al 19: 74 08 je 0x23 1b: 3c 03 cmp $0x3,%al 1d: 0f 8e 26 01 00 00 jle 0x149 23: 89 ab 48 08 00 00 mov %ebp,0x848(%rbx) * 29: 65 48 8b 1c 25 c0 7f mov %gs:0x27fc0,%rbx <-- trapping instruction 30: 02 00 32: 48 8d bb 84 08 00 00 lea 0x884(%rbx),%rdi 39: 48 rex.W 3a: b8 .byte 0xb8 3b: 00 00 add %al,(%rax)