INFO: task syz.0.420:7373 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.420 state:D stack:25864 pid:7373 tgid:7371 ppid:5867 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7020 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776 bdev_open+0xe0/0xd30 block/bdev.c:962 bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1076 setup_bdev_super+0x5a/0x5b0 fs/super.c:1609 get_tree_bdev_flags+0x366/0x4d0 fs/super.c:1689 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1afd38f749 RSP: 002b:00007f1afe285038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f1afd5e6090 RCX: 00007f1afd38f749 RDX: 0000200000000000 RSI: 0000200000000040 RDI: 0000200000000080 RBP: 00007f1afd413f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1afd5e6128 R14: 00007f1afd5e6090 R15: 00007fff4a16fbe8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e33f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e33f2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u9:0/53: #0: ffff88807b19b148 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254 #1: ffffc90000be7b80 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255 #2: ffff88807ae74ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d3/0x400 net/bluetooth/hci_sync.c:331 1 lock held by syslogd/5181: #0: ffff8880b873ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 2 locks held by getty/5583: #0: ffff888034a650a0 (&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+0x449/0x1460 drivers/tty/n_tty.c:2211 2 locks held by kworker/1:3/5936: 1 lock held by udevd/5965: #0: ffff8880259cd358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 2 locks held by syz.0.420/7373: #0: ffff888079c880e0 (&type->s_umount_key#66/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xaa0 fs/super.c:344 #1: ffff8880259cd358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962 2 locks held by syz.7.1105/9856: #0: ffff8880589280e0 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xaa0 fs/super.c:344 #1: ffffffff8e344e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8e344e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:956 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [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:363 [inline] watchdog+0xe40/0xe90 kernel/hung_task.c:557 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6201 Comm: kworker/u8:12 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:arch_static_branch include/trace/events/preemptirq.h:40 [inline] RIP: 0010:trace_irq_enable+0x2/0x100 include/trace/events/preemptirq.h:40 Code: 65 c7 05 1d 7f fb 10 00 00 00 00 c3 cc cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 56 <53> 66 90 65 8b 05 a8 6d fa 10 83 f8 08 73 33 89 c3 c1 e8 06 48 8d RSP: 0018:ffffc9000b3ff728 EFLAGS: 00000002 RAX: 0000000000000001 RBX: ffff8880b8736ab0 RCX: ffff88803435db80 RDX: 0000000000000000 RSI: ffffffff8dc93c7b RDI: ffffffff8528dafc RBP: ffffc9000b3ff830 R08: ffffc9000b3ff6bf R09: 0000000000000000 R10: ffffc9000b3ff680 R11: fffff5200167fed8 R12: dffffc0000000000 R13: ffff8880b8736a90 R14: 0000000000000200 R15: ffff8880b8736ae0 FS: 0000000000000000(0000) GS:ffff888125adc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000755d4000 CR4: 00000000003526f0 Call Trace: trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:73 crng_make_state+0x34c/0x700 drivers/char/random.c:393 _get_random_bytes+0xd5/0x210 drivers/char/random.c:406 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:846 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline] nsim_dev_trap_report_work+0x69e/0xb80 drivers/net/netdevsim/dev.c:922 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 usb 8-1: qt2_read_bulk_callback - non-zero urb status: -71