INFO: task syz-executor.0:16970 blocked for more than 143 seconds. Not tainted 5.15.148-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:24640 pid:16970 ppid: 3534 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 schedule+0x11b/0x1f0 kernel/sched/core.c:6459 schedule_timeout+0xac/0x300 kernel/time/timer.c:1860 do_wait_for_common+0x2d9/0x480 kernel/sched/completion.c:85 __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x48/0x60 kernel/sched/completion.c:138 flush_workqueue+0x737/0x1610 kernel/workqueue.c:2882 nbd_start_device_ioctl drivers/block/nbd.c:1365 [inline] __nbd_ioctl drivers/block/nbd.c:1427 [inline] nbd_ioctl+0xab8/0xe10 drivers/block/nbd.c:1467 blkdev_ioctl+0x333/0x6b0 block/ioctl.c:606 block_ioctl+0xb1/0xf0 block/fops.c:493 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7f06a42c6da9 RSP: 002b:00007f06a28470c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f06a43f4f80 RCX: 00007f06a42c6da9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007f06a431347a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f06a43f4f80 R15: 00007ffea1450c38 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c91f220 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 3 locks held by kworker/u4:1/144: 2 locks held by nbd0-recv/999: #0: ffff88801b802938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc90004d27d20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 2 locks held by getty/3274: #0: ffff88802489f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc90002bae2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158 2 locks held by kworker/u5:2/3540: #0: ffff88801b802938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc90002df7d20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 2 locks held by kworker/u5:3/3542: #0: ffff88801b802938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc90002e07d20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 2 locks held by kworker/u5:4/3543: #0: ffff88801b802938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc90003027d20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 2 locks held by kworker/u5:5/3547: #0: ffff88801b802938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc90003067d20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 2 locks held by kworker/u5:0/16986: #0: ffff88801b802938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc90004f77d20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 2 locks held by kworker/u5:1/16987: #0: ffff88801b802938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283 #1: ffffc900051ffd20 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285 1 lock held by syz-executor.0/17349: 3 locks held by syz-executor.2/21635: 1 lock held by syz-executor.3/21641: #0: ffffffff8cfd1e88 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline] #0: ffffffff8cfd1e88 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x237/0xde0 drivers/tty/tty_io.c:2148 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.148-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline] watchdog+0xe72/0xeb0 kernel/hung_task.c:295 kthread+0x3f6/0x4f0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 21647 Comm: syz-executor.1 Not tainted 5.15.148-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 RIP: 0033:0x7fbe4d9e483b Code: cd 48 01 c1 49 39 4f 08 72 4c 8d 4d ff 85 ed 74 33 66 0f 1f 44 00 00 48 39 f0 72 1b 4d 8b 07 49 89 c1 49 29 f1 47 0f b6 0c 08 <45> 84 c9 74 08 45 88 0c 00 49 8b 47 10 48 83 c0 01 49 89 47 10 83 RSP: 002b:00007fbe4bfb8530 EFLAGS: 00000206 RAX: 00000000005e05c4 RBX: 00007fbe4bfb85d0 RCX: 00000000000000f7 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007fbe4bfb8670 RBP: 0000000000000102 R08: 00007fbe43b99000 R09: 0000000000000000 R10: 0000000000000000 R11: 00007fbe4bfb85e0 R12: 0000000000000001 R13: 00007fbe4daa7cc0 R14: 0000000000000000 R15: 00007fbe4bfb8670 FS: 00007fbe4bfb96c0 GS: 0000000000000000