INFO: task syz.6.5645:29090 blocked for more than 143 seconds. Not tainted 6.13.0-rc3-syzkaller-00026-g59dbb9d81adf #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.6.5645 state:D stack:26848 pid:29090 tgid:29088 ppid:21603 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 __mutex_lock_common kernel/locking/mutex.c:665 [inline] __mutex_lock+0x62b/0xa60 kernel/locking/mutex.c:735 nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 nfsd_umount+0x48/0xe0 fs/nfsd/nfsctl.c:1428 deactivate_locked_super+0xbe/0x1a0 fs/super.c:473 deactivate_super+0xde/0x100 fs/super.c:506 cleanup_mnt+0x222/0x450 fs/namespace.c:1373 task_work_run+0x14e/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f059d185d29 RSP: 002b:00007f059df38038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffea RBX: 00007f059d375fa0 RCX: 00007f059d185d29 RDX: 0000000020000080 RSI: 0000000020000040 RDI: 0000000000000000 RBP: 00007f059d201a20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f059d375fa0 R15: 00007ffe2bc33148 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8ddbad40 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8ddbad40 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8ddbad40 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6744 2 locks held by getty/5588: #0: ffff8880353620a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 2 locks held by kworker/u9:6/5839: #0: ffff8880257c3148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3204 #1: ffffc90003e97d80 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3205 2 locks held by syz.5.5592/28920: #0: ffffffff8fb5df50 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e1bae88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x694/0xbe0 fs/nfsd/nfsctl.c:1671 2 locks held by syz.6.5645/29090: #0: ffff88806e2fe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88806e2fe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88806e2fe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1bae88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 2 locks held by syz.1.5818/29715: #0: ffff888029efe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888029efe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888029efe0e0 (&type->s_umount_key#51){++++}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:505 #1: ffffffff8e1bae88 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:625 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc3-syzkaller-00026-g59dbb9d81adf #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline] watchdog+0xf14/0x1240 kernel/hung_task.c:397 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:111