INFO: task syz.0.18:6469 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.18 state:D stack:27520 pid:6469 tgid:6468 ppid:6339 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1539/0x5080 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2cc/0x5e0 kernel/sched/completion.c:153 __flush_work+0xa17/0xc50 kernel/workqueue.c:4331 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4451 p9_conn_destroy net/9p/trans_fd.c:806 [inline] p9_fd_close+0x251/0x430 net/9p/trans_fd.c:841 p9_client_create+0x68d/0xc90 net/9p/client.c:937 v9fs_session_init+0x46/0xdf0 fs/9p/v9fs.c:442 v9fs_get_tree+0xbd/0xac0 fs/9p/vfs_super.c:97 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3760 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3836 do_mount fs/namespace.c:4159 [inline] __do_sys_mount fs/namespace.c:4348 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4325 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f808939a679 RSP: 002b:00007f808a1fe028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f8089605fa0 RCX: 00007f808939a679 RDX: 0000200000000540 RSI: 0000200000000180 RDI: 0000000000000000 RBP: 00007f808942dee0 R08: 0000200000000580 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8089606038 R14: 00007f8089605fa0 R15: 00007ffe291620a8 Showing all locks held in the system: 2 locks held by kworker/0:0/9: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc900000e7c40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 2 locks held by kworker/0:1/10: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc900000f7c40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 1 lock held by khungtaskd/30: #0: ffffffff8e75dda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75dda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75dda0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/1:1/43: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc90000b37c40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 2 locks held by kworker/0:2/980: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc90003bafc40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 2 locks held by getty/5586: #0: ffff88803237d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 2 locks held by kworker/0:3/5917: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc90003d0fc40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 2 locks held by kworker/1:5/6014: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc90003a07c40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 2 locks held by kworker/1:6/6300: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc90003eefc40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 2 locks held by kworker/0:6/6532: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc9000356fc40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 2 locks held by kworker/1:8/6554: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc90003c3fc40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 3 locks held by kworker/0:8/6618: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc9000422fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 #2: ffff8880351e3240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0 drivers/net/netdevsim/fib.c:1490 2 locks held by kworker/0:9/6625: #0: ffff88813ff0f548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x855/0x15a0 kernel/workqueue.c:3254 #1: ffffc9000423fc40 ((work_completion)(&m->rq)){+.+.}-{0:0}, at: process_one_work+0x87c/0x15a0 kernel/workqueue.c:3255 4 locks held by kworker/u8:16/6657: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 37 7b 02 e9 83 e7 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 5e 2b 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8e407dc0 EFLAGS: 00000242 RAX: 00000000001bdc0b RBX: ffffffff8199daad RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8dedf4c2 RDI: ffffffff8c275600 RBP: ffffffff8e407eb0 R08: ffff8880b843375b R09: 1ffff110170866eb R10: dffffc0000000000 R11: ffffed10170866ec R12: ffffffff901007b0 R13: 1ffffffff1c929d8 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881252be000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8ef36b5ff8 CR3: 000000007e8a0000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1bd/0x500 kernel/sched/idle.c:332 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:760 start_kernel+0x385/0x3d0 init/main.c:1210 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147