NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 INFO: task syz-executor.2:8408 blocked for more than 140 seconds. Not tainted 4.14.195-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28504 8408 6385 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1731 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 flush_workqueue+0x3ce/0x1310 kernel/workqueue.c:2676 nbd_start_device_ioctl drivers/block/nbd.c:1254 [inline] __nbd_ioctl drivers/block/nbd.c:1325 [inline] nbd_ioctl+0x49d/0xa80 drivers/block/nbd.c:1365 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1883 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: 0033:0x45d5b9 RSP: 002b:00007f95a664fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000000129c0 RCX: 000000000045d5b9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000118cf78 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffccf838f8f R14: 00007f95a66509c0 R15: 000000000118cf4c Showing all locks held in the system: 1 lock held by khungtaskd/1047: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by kworker/u5:7/6431: #0: ("knbd%d-recv"nbd->index){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2087 #1: ((&args->work)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1047 Comm: khungtaskd Not tainted 4.14.195-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+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: 3637 Comm: systemd-journal Not tainted 4.14.195-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff888094e56680 task.stack: ffff888094e58000 RIP: 0010:preempt_latency_start kernel/sched/core.c:3087 [inline] RIP: 0010:preempt_count_add+0xd8/0x170 kernel/sched/core.c:3110 RSP: 0018:ffff888094e5fcf0 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff110129caf17 RSI: 0000000000000000 RDI: ffff888094e578b8 RBP: ffff888094e56680 R08: ffffffff8a083a68 R09: 0000000000000000 R10: 0000000000000000 R11: ffff888094e56680 R12: 0000000000000086 R13: fffffbfff14e8998 R14: ffff88809a404040 R15: 0000000000000000 FS: 00007ff2350998c0(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff232492000 CR3: 0000000094e0f000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:109 [inline] _raw_spin_lock_irqsave+0x70/0xc0 kernel/locking/spinlock.c:160 __debug_check_no_obj_freed lib/debugobjects.c:738 [inline] debug_check_no_obj_freed+0x135/0x674 lib/debugobjects.c:776 kmem_cache_free+0x156/0x2b0 mm/slab.c:3757 putname+0xcd/0x110 fs/namei.c:259 do_sys_open+0x203/0x410 fs/open.c:1090 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7ff234629840 RSP: 002b:00007ffe839c5768 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007ffe839c5a70 RCX: 00007ff234629840 RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 000055ef79535a50 RBP: 000000000000000d R08: 0000000000000000 R09: 00000000ffffffff R10: 0000000000000069 R11: 0000000000000246 R12: 00000000ffffffff R13: 000055ef79529060 R14: 00007ffe839c5a30 R15: 000055ef79535870 Code: 09 00 85 c0 75 31 65 48 8b 2c 25 40 ee 01 00 48 8d bd 38 12 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <75> 79 48 89 9d 38 12 00 00 5b 5d c3 31 ff 31 db e8 f3 21 09 00