INFO: tas
INFO: task kworker/1:8:5747 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:8 state:D stack:20560 pid:5747 tgid:5747 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5526 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7276
__schedule_loop kernel/sched/core.c:7353 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7368
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7425
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
hub_port_connect drivers/usb/core/hub.c:5478 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
port_event drivers/usb/core/hub.c:5884 [inline]
hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5966
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 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
Showing all locks held in the system:
locks held by khungtaskd/32: 1, last CPU#0:
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:6/505: 3, last CPU#1:
#0: ffff888051a94140 ((wq_completion)krds_cp_wq#10/0){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888051a94140 ((wq_completion)krds_cp_wq#10/0){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888051a94140 ((wq_completion)krds_cp_wq#10/0){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888051a94140 ((wq_completion)krds_cp_wq#10/0){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90003ae7c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90003ae7c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90003ae7c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90003ae7c40 ((work_completion)(&(&cp->cp_conn_w)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffff888054cca180 (&tc->t_conn_path_lock){+.+.}-{4:4}, at: rds_tcp_conn_path_connect+0x1cc/0x920 net/rds/tcp_connect.c:118
locks held by kworker/u8:7/712: 1, last CPU#1:
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffffffff8ed5c8a0 (rcu_read_lock){....}-{1:3}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by getty/5377: 2, on CPU#0:
#0: ffff8880362b40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by udevd/5630: 4, on CPU#0:
#0: ffff888055a6ff38 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa4/0xca0 fs/seq_file.c:183
#1: ffff88807e8b0880 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165
#2: ffff88802aa234b8 (kn->active#30){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff88802aa234b8 (kn->active#30){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:166
#3: ffff888078a461d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1109 [inline]
#3: ffff888078a461d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
locks held by kworker/0:5/5679: 5, on CPU#0:
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc900045e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc900045e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc900045e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc900045e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffff88802aba81d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802aba81d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5912
#3: ffff88802abac568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3265 [inline]
#3: ffff88802abac568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5477 [inline]
#3: ffff88802abac568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
#3: ffff88802abac568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5884 [inline]
#3: ffff88802abac568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x20a1/0x4d30 drivers/usb/core/hub.c:5966
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5478 [inline]
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5884 [inline]
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5966
locks held by kworker/0:6/5686: 5, on CPU#0:
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90004a67c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004a67c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004a67c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90004a67c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffff888029ff11d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff888029ff11d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5912
#3: ffff888078a461d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#3: ffff888078a461d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
#4: ffff888034ace1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff888034ace1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073
locks held by kworker/1:8/5747: 5, on CPU#1:
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888022eac940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90004df7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004df7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004df7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90004df7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffff88802ab711d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802ab711d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5912
#3: ffff88802ab75568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3265 [inline]
#3: ffff88802ab75568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5477 [inline]
#3: ffff88802ab75568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
#3: ffff88802ab75568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5884 [inline]
#3: ffff88802ab75568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x20a1/0x4d30 drivers/usb/core/hub.c:5966
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5478 [inline]
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5884 [inline]
#4: ffff88802aaf0560 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x20c9/0x4d30 drivers/usb/core/hub.c:5966
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/08/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x38b/0x480 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 505 Comm: kworker/u8:6 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/08/2026
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:101 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
RIP: 0010:unwind_next_frame+0x4c3/0x2550 arch/x86/kernel/unwind_orc.c:510
Code: 01 4c 8b 6c 24 50 49 bc 00 00 00 00 00 fc ff df 4c 8b 7c 24 10 49 8d 6e 38 0f 84 8a 16 00 00 e9 ee 01 00 00 49 89 d5 49 89 d7 <4c> 89 e0 4c 29 f8 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83
RSP: 0000:ffffc90003ae7060 EFLAGS: 00000297
RAX: ffffffff908fba60 RBX: ffffffff908fba64 RCX: ffffffff908fba68
RDX: ffffffff908fba48 RSI: ffffffff910c9ac6 RDI: ffffffff8c6d9a20
RBP: ffffffff81331039 R08: 0000000000000015 R09: 0000000000000000
R10: ffffc90003ae7158 R11: ffffffff81b285d0 R12: ffffffff908fba6c
R13: ffffffff908fba64 R14: ffffc90003ae7108 R15: ffffffff908fba68
FS: 0000000000000000(0000) GS:ffff888124dd2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000033f07ff8 CR3: 000000001fef0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3181 [inline]
call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3301
refdst_drop include/net/dst.h:272 [inline]
skb_dst_drop include/net/dst.h:284 [inline]
skb_release_head_state+0x71/0x370 net/core/skbuff.c:1171
skb_release_all net/core/skbuff.c:1195 [inline]
__kfree_skb+0x24/0x210 net/core/skbuff.c:1211
kfree_skb_reason include/linux/skbuff.h:1323 [inline]
kfree_skb include/linux/skbuff.h:1332 [inline]
nf_queue+0xd91/0x1520 net/netfilter/nf_queue.c:262
nf_hook_slow+0x109/0x220 net/netfilter/core.c:631
nf_hook include/linux/netfilter.h:280 [inline]
NF_HOOK include/linux/netfilter.h:323 [inline]
ndisc_send_skb+0x14e0/0x1650 net/ipv6/ndisc.c:513
ndisc_send_ns+0xd7/0x160 net/ipv6/ndisc.c:672
addrconf_dad_work+0xa8d/0x15c0 net/ipv6/addrconf.c:4318
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 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