INFO: task syz.0.15:6727 blocked for more than 143 seconds. Not tainted 6.14.0-rc3-syzkaller-g2408a807bfc3 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.15 state:D stack:27824 pid:6727 tgid:6716 ppid:6518 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6857 schedule_timeout+0x244/0x280 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x3e1/0x600 kernel/sched/completion.c:116 __flush_workqueue+0x3dc/0x1260 kernel/workqueue.c:3998 nbd_start_device_ioctl drivers/block/nbd.c:1541 [inline] __nbd_ioctl drivers/block/nbd.c:1602 [inline] nbd_ioctl+0x308/0xd60 drivers/block/nbd.c:1642 blkdev_ioctl+0x276/0x6d0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe34df7fed9 RSP: 002b:00007fe34ee23058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe34e146080 RCX: 00007fe34df7fed9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007fe34dff3cc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fe34e146080 R15: 00007ffe550a1708 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e1bcc80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e1bcc80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e1bcc80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746 2 locks held by kworker/u9:0/54: #0: ffff888025edc148 ((wq_completion)nbd4-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90000bf7d18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:1/5132: #0: ffff888025d2d948 ((wq_completion)nbd2-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc9000e987d18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by getty/5574: #0: ffff888031f6f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900032fb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 2 locks held by kworker/u9:2/5875: #0: ffff888025c93148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc9000400fd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:3/6749: #0: ffff888025d29148 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90002df7d18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:4/6769: #0: ffff888025e63948 ((wq_completion)nbd3-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90002e67d18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:5/6787: #0: ffff888025fe6148 ((wq_completion)nbd8-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90003557d18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:6/6807: #0: ffff888025ef3148 ((wq_completion)nbd6-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90003d7fd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:7/6832: #0: ffff888143788148 ((wq_completion)nbd5-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90003e6fd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:8/6855: #0: ffff888026009948 ((wq_completion)nbd7-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90003f2fd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 2 locks held by kworker/u9:9/6881: #0: ffff888143788948 ((wq_completion)nbd9-recv){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc90003fdfd18 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc3-syzkaller-g2408a807bfc3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 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:236 [inline] watchdog+0xf62/0x12b0 kernel/hung_task.c:399 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 35 Comm: kworker/u8:2 Not tainted 6.14.0-rc3-syzkaller-g2408a807bfc3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:mutex_trylock+0x37/0x140 kernel/locking/mutex.c:1067 Code: ba 00 00 00 00 00 fc ff df 48 89 c1 53 83 e0 07 48 89 fb 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 d2 00 00 00 <8b> 0d d3 78 33 0f 85 c9 75 25 48 8d 7b 60 48 b8 00 00 00 00 00 fc RSP: 0018:ffffc90000ab7b88 EFLAGS: 00000297 RAX: 0000000000000003 RBX: ffff888027d311e8 RCX: 1ffffffff3517b14 RDX: 0000000000000004 RSI: ffffffff8a36376d RDI: ffff888027d311e8 RBP: ffff8880737b9800 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 000000000003d94c R13: ffff888027d31360 R14: 0000000000000000 R15: ffff88801b092000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005593d2060a58 CR3: 000000000df80000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: nsim_dev_trap_report_work+0x56/0xd00 drivers/net/netdevsim/dev.c:838 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244