INFO: task syz.1.1289:9784 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.1.1289 state:D stack:28920 pid:9784 tgid:9783 ppid:5612 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5402 [inline] __schedule+0x16f9/0x5500 kernel/sched/core.c:7204 __schedule_loop kernel/sched/core.c:7283 [inline] schedule+0x164/0x360 kernel/sched/core.c:7298 cgroup_lock_and_drain_offline+0x516/0x650 kernel/cgroup/cgroup.c:3248 cgroup1_get_tree+0xa2/0x8a0 kernel/cgroup/cgroup-v1.c:1265 vfs_get_tree+0x92/0x2a0 fs/super.c:1753 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3763 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3839 do_mount fs/namespace.c:4172 [inline] __do_sys_mount fs/namespace.c:4388 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4365 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f10787ece59 RSP: 002b:00007f1076a46028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f1078a65fa0 RCX: 00007f10787ece59 RDX: 0000200000000200 RSI: 00002000000001c0 RDI: 0000000000000000 RBP: 00007f1078882d6f R08: 0000200000000240 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1078a66038 R14: 00007f1078a65fa0 R15: 00007ffd133a8508 Showing all locks held in the system: 1 lock held by khungtaskd/39: #0: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff8e1cac60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777 2 locks held by getty/5367: #0: ffff8880368060a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211 4 locks held by udevd/5614: #0: ffff8880278ae4f0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb8/0xe20 fs/seq_file.c:183 #1: ffff88803b81b078 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172 #2: ffff888025b78d28 (kn->active#27){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888025b78d28 (kn->active#27){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173 #3: ffff88801231c210 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1107 [inline] #3: ffff88801231c210 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:5/5626: #0: ffff88802128d538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293 #1: ffffc9000519fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294 #2: ffff888021bbc210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #2: ffff888021bbc210 (&dev->mutex){....}-{4:4}, at: hub_event+0x17c/0x4f60 drivers/usb/core/hub.c:5899 #3: ffff88806e1f8210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #3: ffff88806e1f8210 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073 #4: ffff88805dfdd1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #4: ffff88805dfdd1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073 #5: ffffffff8e0689a0 (umhelper_sem){++++}-{4:4}, at: usermodehelper_read_trylock+0xfc/0x2c0 kernel/umh.c:214 5 locks held by kworker/1:5/5725: #0: ffff88802128d538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293 #1: ffffc900058a7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294 #2: ffff888022352210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #2: ffff888022352210 (&dev->mutex){....}-{4:4}, at: hub_event+0x17c/0x4f60 drivers/usb/core/hub.c:5899 #3: ffff88801231c210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #3: ffff88801231c210 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073 #4: ffff88801b320318 (&(&priv->bus_notifier)->rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90 kernel/notifier.c:379 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [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:353 [inline] watchdog+0xfd3/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 0b 67 02 c3 cc cc cc cc 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 43 13 0f 00 fb f4 3c cb 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8de07dc0 EFLAGS: 00000246 RAX: 00000000003042cf RBX: ffffffff8199f80a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d769ba8 RDI: ffffffff8bac2180 RBP: ffffffff8de07eb0 R08: ffff8880b8633d5b R09: 1ffff110170c67ab R10: dffffc0000000000 R11: ffffed10170c67ac R12: 0000000000000000 R13: 1ffffffff1bdfde8 R14: 0000000000000000 R15: 1ffffffff1bdfde8 FS: 0000000000000000(0000) GS:ffff888125c7e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e9acd2c638 CR3: 0000000042688000 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:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 rest_init+0x2de/0x300 init/main.c:717 start_kernel+0x392/0x3e0 init/main.c:1175 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/0x157