INFO: task syz.2.4664:17082 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.2.4664 state:D stack:28184 pid:17082 tgid:17081 ppid:5841 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
device_lock include/linux/device.h:895 [inline]
usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414
do_dentry_open+0x7ce/0x1420 fs/open.c:962
vfs_open+0x3b/0x340 fs/open.c:1094
do_open fs/namei.c:4628 [inline]
path_openat+0x340e/0x3dd0 fs/namei.c:4787
do_filp_open+0x1fa/0x410 fs/namei.c:4814
do_sys_openat2+0x121/0x200 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_openat fs/open.c:1452 [inline]
__se_sys_openat fs/open.c:1447 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1447
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f493058df90
RSP: 002b:00007f493136fb70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000000000000a401 RCX: 00007f493058df90
RDX: 000000000000a401 RSI: 00007f493136fc10 RDI: 00000000ffffff9c
RBP: 00007f493136fc10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007f49307e6038 R14: 00007f49307e5fa0 R15: 00007f493090fa28
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/5199:
2 locks held by getty/5589:
#0: ffff88814d1950a0 (&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/0:9/5942:
9 locks held by kworker/0:10/8749:
2 locks held by kworker/0:20/13823:
1 lock held by syz.2.4664/17082:
#0: ffff888144f49198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#0: ffff888144f49198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x16e/0x760 drivers/usb/core/devio.c:1054
4 locks held by syz.1.6293/22035:
2 locks held by syz.4.6291/22031:
2 locks held by syz.3.6294/22032:
2 locks held by syz.0.6292/22033:
=============================================
NMI backtrace for cpu 1
CPU: 1 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+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: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:346 [inline]
watchdog+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8749 Comm: kworker/0:10 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: usb_hub_wq hub_event
RIP: 0010:__lock_acquire+0x82a/0x2cf0 kernel/locking/lockdep.c:-1
Code: 7c d3 e9 b4 00 00 00 48 c7 c7 30 20 e1 8d 4c 89 fe e8 2a fd 28 03 eb c3 89 e8 25 ff 1f 00 00 c1 ed 03 81 e5 00 60 00 00 09 c5 <48> 89 d8 48 c1 e8 20 29 c5 89 c1 c1 c1 04 31 e9 01 d8 29 cb 89 ca
RSP: 0018:ffffc90000006810 EFLAGS: 00000002
RAX: 0000000000000007 RBX: 39529a686290c103 RCX: 0000000000000000
RDX: 0000000000000008 RSI: ffff888024b42af0 RDI: ffff888024b41e80
RBP: 0000000000004007 R08: ffffffff8173fd65 R09: ffffffff8df41aa0
R10: ffffc90000006b18 R11: ffffffff81acf3d0 R12: ffff888024b42af0
R13: ffff888024b42af0 R14: ffff888024b41e80 R15: 0000000000000008
FS: 0000000000000000(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f18d5af98 CR3: 000000000dd3a000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6670 [inline]
kmem_cache_free+0x197/0x620 mm/slub.c:6781
kfree_skb_reason include/linux/skbuff.h:1322 [inline]
kfree_skb include/linux/skbuff.h:1331 [inline]
ip6_mc_input+0x8de/0xb70 net/ipv6/ip6_input.c:593
ip_sabotage_in+0x1e1/0x270 net/bridge/br_netfilter_hooks.c:990
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
__netif_receive_skb_one_core net/core/dev.c:6139 [inline]
__netif_receive_skb+0xd3/0x380 net/core/dev.c:6252
netif_receive_skb_internal net/core/dev.c:6338 [inline]
netif_receive_skb+0x1bb/0x750 net/core/dev.c:6397
NF_HOOK+0xa0/0x390 include/linux/netfilter.h:319
br_handle_frame_finish+0x15c6/0x1c90 net/bridge/br_input.c:235
br_nf_hook_thresh+0x3c6/0x4a0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0x999/0xd60 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:318 [inline]
br_nf_pre_routing_ipv6+0x37e/0x6b0 net/bridge/br_netfilter_ipv6.c:184
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0x96e/0x14f0 net/bridge/br_input.c:442
__netif_receive_skb_core+0x95f/0x2f90 net/core/dev.c:6026
__netif_receive_skb_one_core net/core/dev.c:6137 [inline]
__netif_receive_skb+0x72/0x380 net/core/dev.c:6252
process_backlog+0x54f/0x1340 net/core/dev.c:6604
__napi_poll+0xae/0x320 net/core/dev.c:7668
napi_poll net/core/dev.c:7731 [inline]
net_rx_action+0x64a/0xe00 net/core/dev.c:7883
handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
local_bh_enable include/linux/bottom_half.h:33 [inline]
__alloc_skb+0x1bc/0x3a0 net/core/skbuff.c:674
__netdev_alloc_skb+0xc1/0x850 net/core/skbuff.c:754
netdev_alloc_skb include/linux/skbuff.h:3484 [inline]
dev_alloc_skb include/linux/skbuff.h:3497 [inline]
ath6kl_usb_post_recv_transfers+0x207/0x6f0 drivers/net/wireless/ath/ath6kl/usb.c:428
ath6kl_usb_start_recv_pipes drivers/net/wireless/ath/ath6kl/usb.c:498 [inline]
hif_start drivers/net/wireless/ath/ath6kl/usb.c:703 [inline]
ath6kl_usb_power_on+0x6a/0x280 drivers/net/wireless/ath/ath6kl/usb.c:1062
ath6kl_hif_power_on drivers/net/wireless/ath/ath6kl/hif-ops.h:136 [inline]
ath6kl_core_init+0x1d9/0x10f0 drivers/net/wireless/ath/ath6kl/core.c:97
ath6kl_usb_probe+0x14df/0x15d0 drivers/net/wireless/ath/ath6kl/usb.c:1168
usb_probe_interface+0x668/0xc90 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x26d/0xad0 drivers/base/dd.c:659
__driver_probe_device+0x18c/0x320 drivers/base/dd.c:801
driver_probe_device+0x4f/0x240 drivers/base/dd.c:831
__device_attach_driver+0x279/0x430 drivers/base/dd.c:959
bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:500
__device_attach+0x2b8/0x430 drivers/base/dd.c:1031
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1086
bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
device_add+0x7b6/0xb80 drivers/base/core.c:3689
usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
usb_probe_device+0x1c4/0x3c0 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x26d/0xad0 drivers/base/dd.c:659
__driver_probe_device+0x18c/0x320 drivers/base/dd.c:801
driver_probe_device+0x4f/0x240 drivers/base/dd.c:831
__device_attach_driver+0x279/0x430 drivers/base/dd.c:959
bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:500
__device_attach+0x2b8/0x430 drivers/base/dd.c:1031
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1086
bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
device_add+0x7b6/0xb80 drivers/base/core.c:3689
usb_new_device+0xa39/0x1720 drivers/usb/core/hub.c:2695
hub_port_connect drivers/usb/core/hub.c:5567 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x29b1/0x4ef0 drivers/usb/core/hub.c:5953
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246