EXT4-fs (loop0): re-mounted. Opts: (null) EXT4-fs (loop0): re-mounted. Opts: (null) EXT4-fs (loop0): re-mounted. Opts: (null) EXT4-fs (loop0): re-mounted. Opts: (null) INFO: task syz-executor419:7971 blocked for more than 140 seconds. Not tainted 4.14.284-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor419 D28344 7971 7969 0x00000000 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_timeout+0x80a/0xe90 kernel/time/timer.c:1724 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 kthread_stop+0xce/0x640 kernel/kthread.c:555 ext4_put_super+0x865/0xf00 fs/ext4/super.c:988 generic_shutdown_super+0x144/0x370 fs/super.c:446 kill_block_super+0x95/0xe0 fs/super.c:1161 deactivate_locked_super+0x6c/0xd0 fs/super.c:319 deactivate_super+0x7f/0xa0 fs/super.c:350 cleanup_mnt+0x186/0x2c0 fs/namespace.c:1183 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f242229b3e7 RSP: 002b:00007ffe86c74948 EFLAGS: 00000206 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f242229b3e7 RDX: 00007ffe86c74a0b RSI: 000000000000000a RDI: 00007ffe86c74a00 RBP: 00007ffe86c74a00 R08: 00000000ffffffff R09: 00007ffe86c747e0 R10: 0000555556100683 R11: 0000000000000206 R12: 00007ffe86c75a70 R13: 00005555561005f0 R14: 00007ffe86c74970 R15: 00000000000000f0 Showing all locks held in the system: 1 lock held by khungtaskd/1532: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by syz-executor419/7971: #0: (&type->s_umount_key#36){++++}, at: [] deactivate_super+0x77/0xa0 fs/super.c:349 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1532 Comm: khungtaskd Not tainted 4.14.284-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 skipped: idling at pc 0xffffffff872480fe