INFO: task syz.7.2650:15212 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.7.2650 state:D stack:24000 pid:15212 tgid:15211 ppid:9096 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5352 [inline]
__schedule+0x165c/0x5560 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7047 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7062
schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2cc/0x5e0 kernel/sched/completion.c:153
__flush_work+0xa17/0xc50 kernel/workqueue.c:4358
p9_mux_poll_stop net/9p/trans_fd.c:140 [inline]
p9_conn_destroy net/9p/trans_fd.c:804 [inline]
p9_fd_close+0x245/0x430 net/9p/trans_fd.c:840
p9_client_create+0x68d/0xc90 net/9p/client.c:937
v9fs_session_init+0x46/0xdf0 fs/9p/v9fs.c:442
v9fs_get_tree+0xbd/0xac0 fs/9p/vfs_super.c:97
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3764 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3840
do_mount fs/namespace.c:4173 [inline]
__do_sys_mount fs/namespace.c:4372 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4349
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc5c979c799
RSP: 002b:00007fc5ca599028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fc5c9a15fa0 RCX: 00007fc5c979c799
RDX: 0000200000000140 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007fc5c9832c99 R08: 00002000000002c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc5c9a16038 R14: 00007fc5c9a15fa0 R15: 00007ffd1df7cb88
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e75d7e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e75d7e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e75d7e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:2/35:
#0: ffff88801c2b6140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3260
#1: ffffc90000ab7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3261
#2: ffffffff8fbc6588 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675
#3: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xe5/0xa00 net/core/dev.c:13092
#4: ffffffff8e763a28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#4: ffffffff8e763a28 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
4 locks held by kworker/1:2/807:
#0: ffff8880222fb140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3260
#1: ffffc90004b97c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3261
#2: ffff88802b6851d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:995 [inline]
#2: ffff88802b6851d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899
#3: ffff8880673f71d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:995 [inline]
#3: ffff8880673f71d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1068
1 lock held by dhcpcd/5508:
#0: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x32b/0x1b30 net/ipv4/devinet.c:1120
2 locks held by getty/5598:
#0: ffff8880370d20a0 (&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+0x45c/0x13a0 drivers/tty/n_tty.c:2211
4 locks held by udevd/5899:
#0: ffff888051368cf8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:183
#1: ffff8880323f0480 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
#2: ffff888052587b48 (kn->active#31){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff888052587b48 (kn->active#31){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
#3: ffff8880673f71d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1000 [inline]
#3: ffff8880673f71d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
2 locks held by kworker/1:3/5920:
#0: ffff88801b06b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3260
#1: ffffc90004cb7c40 (p9_poll_work){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3261
3 locks held by kworker/u8:12/6204:
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x890/0x1710 kernel/workqueue.c:3260
#1: ffffc9000537fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x8b7/0x1710 kernel/workqueue.c:3261
#2: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
1 lock held by syz-executor/16971:
#0: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071
2 locks held by syz.4.3203/17069:
3 locks held by syz.4.3203/17106:
2 locks held by syz.8.3210/17105:
#0: ffffffff8fc43a88 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8fbd5580 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x8e0 net/wireless/nl80211.c:18128
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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: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+0x51e/0xb90 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: 35 Comm: kworker/u8:2 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: netns cleanup_net
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 3e b6 84 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 5f 08 ee fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 da d9 71 06 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000ab7110 EFLAGS: 00000002
RAX: 1ffffffff34bcb00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffffff9a5e6070 R08: ffff888026e08237 R09: 1ffff11004dc1046
R10: dffffc0000000000 R11: ffffffff85419580 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9a5e5de0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125549000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcbfd7e7158 CR3: 0000000069aee000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1a1/0x2f0 drivers/tty/serial/8250/8250_port.c:1970
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline]
serial8250_console_write+0x1348/0x1ba0 drivers/tty/serial/8250/8250_port.c:3357
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record kernel/printk/printk.c:3269 [inline]
console_flush_all+0x718/0xb20 kernel/printk/printk.c:3343
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
_printk+0xdd/0x130 kernel/printk/printk.c:2504
batadv_hardif_deactivate_interface net/batman-adv/hard-interface.c:691 [inline]
batadv_hardif_disable_interface+0x1bd/0xaf0 net/batman-adv/hard-interface.c:822
batadv_meshif_destroy_netlink+0x68/0x250 net/batman-adv/mesh-interface.c:1093
default_device_exit_batch+0x764/0xa00 net/core/dev.c:13101
ops_exit_list net/core/net_namespace.c:205 [inline]
ops_undo_list+0x52b/0x940 net/core/net_namespace.c:252
cleanup_net+0x56b/0x800 net/core/net_namespace.c:704
process_one_work+0x9a3/0x1710 kernel/workqueue.c:3288
process_scheduled_works kernel/workqueue.c:3379 [inline]
worker_thread+0xba8/0x11e0 kernel/workqueue.c:3465
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245