[ 529.153466][ T38] INFO: task syz.5.1649:11327 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.5.1649 state:D stack:23416 pid:11327 tgid:11325 ppid:7720 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+0x15f/0x560 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9f6407ce59
RSP: 002b:00007f9f622b5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9f642f6090 RCX: 00007f9f6407ce59
RDX: 00002000000001c0 RSI: 0000200000000100 RDI: 0000000000000000
RBP: 00007f9f64112d6f R08: 0000200000000180 R09: 0000000000000000
R10: 0000000002010042 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9f642f6128 R14: 00007f9f642f6090 R15: 00007ffe7b479bb8
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6777
7 locks held by kworker/u8:13/3304:
#0: ffff88801bade138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293
#1: ffffc9000e327c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294
#2: ffffffff8f590e00 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
#3: ffff88801c6a3348 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3f/0x140 fs/kernfs/dir.c:1792
#4: ffff88801c6a3238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x4e/0x140 fs/kernfs/dir.c:1793
#5: ffff88801c6a3100 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#5: ffff88801c6a3100 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: kernfs_put+0x213/0x700 fs/kernfs/dir.c:614
#6: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rtlock_slowlock_locked+0x2a8/0x3c80 kernel/locking/rtmutex.c:1870
2 locks held by getty/5371:
#0: ffff888032f190a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cbe2e0
(&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
5 locks held by kworker/1:4/5710:
#0: ffff88801afcd138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x897/0x1630 kernel/workqueue.c:3293
#1: ffffc90005037c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8be/0x1630 kernel/workqueue.c:3294
#2: ffff888021bc2210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1038 [inline]
#2: ffff888021bc2210 (&dev->mutex){....}-{4:4}, at: hub_event+0x17c/0x4f60 drivers/usb/core/hub.c:5899
#3: ffff8880217de658 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline]
#3: ffff8880217de658 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
#3: ffff8880217de658 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
#3: ffff8880217de658 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
#3: ffff8880217de658 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b0/0x4f60 drivers/usb/core/hub.c:5953
#4: ffff88802a680158 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline]
#4: ffff88802a680158 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
#4: ffff88802a680158 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
#4: ffff88802a680158 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e0/0x4f60 drivers/usb/core/hub.c:5953
5 locks held by syz.0.2408/13950:
#0: ffff888036b03a30 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:592 [inline]
#0: ffff888036b03a30 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x194/0x9e0 mm/mmap.c:1284
#1: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
#2: ffff88803a0e4c58 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff88803a0e4c58 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#4: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#4: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#4: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: page_table_check_clear+0x124/0x4f0 mm/page_table_check.c:77
8 locks held by syz.0.2408/13951:
#0: ffffffff8f590e00 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575
#1: ffffffff8f5a0338 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
#1: ffffffff8f5a0338 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11557
#2: ffff8880b873a148 ((lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#2: ffff8880b873a148 ((lock)){+.+.}-{3:3}, at: __radix_tree_preload+0x141/0x870 lib/radix-tree.c:334
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#4: ffff88801c6a3100 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
#4: ffff88801c6a3100 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: __kernfs_new_node+0x112/0x980 fs/kernfs/dir.c:669
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#5: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
#6: ffff8880b8742428 ((&pcs->lock)){+.+.}-{3:3}, at: alloc_from_pcs mm/slub.c:4757 [inline]
#6: ffff8880b8742428 ((&pcs->lock)){+.+.}-{3:3}, at: slab_alloc_node mm/slub.c:4897 [inline]
#6: ffff8880b8742428 ((&pcs->lock)){+.+.}-{3:3}, at: kmem_cache_alloc_noprof+0x1a3/0x680 mm/slub.c:4919
#7: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#7: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#7: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_trylock kernel/locking/spinlock_rt.c:110 [inline]
#7: ffffffff8e1cabc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_trylock+0x10c/0x2b0 kernel/locking/spinlock_rt.c:118
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:119
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:62
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: 3304 Comm: kworker/u8:13 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: netns cleanup_net
RIP: 0010:visit_lock_entry kernel/locking/lockdep.c:1538 [inline]
RIP: 0010:__bfs kernel/locking/lockdep.c:1818 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1862 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2798 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3171 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3286 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3910 [inline]
RIP: 0010:__lock_acquire+0x1974/0x2d10 kernel/locking/lockdep.c:5239
Code: 00 14 2b 05 3e 3c 00 14 25 ff 0f 00 00 39 05 ff 3b ff 11 73 06 89 05 f7 3b ff 11 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff <4c> 89 60 30 48 8b 00 4c 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89
RSP: 0018:ffffc9000e326f70 EFLAGS: 00000002
RAX: ffffffff9630a9f8 RBX: 00000000000003cd RCX: 00000000000006a4
RDX: ffffffff96252538 RSI: ffff88803336ac40 RDI: 00000000000003cd
RBP: 15d337a7244f5b37 R08: ffffc9000e326f38 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff81a19ea0 R12: ffffffff962525a8
R13: ffffffff93427988 R14: ffff888033369f00 R15: 00000000000006a3
FS: 0000000000000000(0000) GS:ffff888125c94000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000020f40000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5870
seqcount_lockdep_reader_access+0x55/0x100 include/linux/seqlock.h:73
ktime_get+0x45/0x220 kernel/time/timekeeping.c:965
hrtick_schedule_exit kernel/sched/core.c:994 [inline]
finish_lock_switch kernel/sched/core.c:5138 [inline]
finish_task_switch+0x312/0xbe0 kernel/sched/core.c:5257
context_switch kernel/sched/core.c:5405 [inline]
__schedule+0x1701/0x5500 kernel/sched/core.c:7204
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7528
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_callee_save___kvm_vcpu_is_preempted+0x13/0x20
Code: 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 48 8b 04 fd 90 87 a0 8d 80 b8 50 fe 98 92 00 <0f> 95 c0 c3 cc cc cc cc 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000e327578 EFLAGS: 00000246
RAX: ffff888125d94000 RBX: 1ffff110052933e2 RCX: 1ffff110038d461f
RDX: 00000000f9455519 RSI: ffffffff8babe060 RDI: 0000000000000001
RBP: ffffc9000e3277d0 R08: ffffffff8b3a9428 R09: ffffffff8e1cabc0
R10: dffffc0000000000 R11: fffffbfff1f5be9f R12: 1ffff110052933e6
R13: ffff888029499f00 R14: ffff88801c6a30f8 R15: ffff88801c6a30f0
pv_vcpu_is_preempted include/linux/sched.h:2306 [inline]
vcpu_is_preempted arch/x86/include/asm/paravirt-spinlock.h:78 [inline]
owner_on_cpu include/linux/sched.h:2361 [inline]
rtmutex_spin_on_owner kernel/locking/rtmutex.c:1520 [inline]
rtlock_slowlock_locked+0x34e5/0x3c80 kernel/locking/rtmutex.c:1889
rtlock_slowlock kernel/locking/rtmutex.c:1918 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x165/0x400 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:45 [inline]
kernfs_put+0x213/0x700 fs/kernfs/dir.c:614
kernfs_remove_by_name_ns+0xc8/0x140 fs/kernfs/dir.c:1799
class_remove_file_ns+0x124/0x160 drivers/base/class.c:153
ops_pre_exit_list net/core/net_namespace.c:161 [inline]
ops_undo_list+0x187/0x940 net/core/net_namespace.c:234
cleanup_net+0x56e/0x800 net/core/net_namespace.c:702
process_one_work+0x98b/0x1630 kernel/workqueue.c:3318
process_scheduled_works kernel/workqueue.c:3401 [inline]
worker_thread+0xb49/0x1140 kernel/workqueue.c:3482
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