[syzbot] [libertas?] INFO: task hung in lbs_remove_card

syzbot
2025-08-14T09:42:33Z

Hello,

syzbot found the following issue on:

HEAD commit: 2b38afce25c4 Merge tag 'turbostat-2025.09.09' of git://git..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=142f4af0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=fc65f9fdda222232
dashboard link: https://syzkaller.appspot.com/bug?extid=c99d17aa44dbdba16ad2
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/03c1659365fe/disk-2b38afce.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c24a7ba0c087/vmlinux-2b38afce.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ae60f96c7e73/bzImage-2b38afce.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c99d17aa44dbdba16ad2@syzkaller.appspotmail.com

INFO: task kworker/1:5:10878 blocked for more than 143 seconds.
Not tainted 6.16.0-syzkaller-12288-g2b38afce25c4 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:5 state:D
stack:21576 pid:10878 tgid:10878 ppid:2 task_flags:0x4288060 flags:0x00004000
Workqueue: events request_firmware_work_func
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x12fc/0x3b90 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7058
lbs_wait_for_firmware_load+0x11e/0x1e0 drivers/net/wireless/marvell/libertas/firmware.c:116
lbs_remove_card+0x84/0x390 drivers/net/wireless/marvell/libertas/main.c:913
if_usb_disconnect+0xaf/0x2e0 drivers/net/wireless/marvell/libertas/if_usb.c:316
usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:571 [inline]
device_remove+0x125/0x170 drivers/base/dd.c:563
__device_release_driver drivers/base/dd.c:1274 [inline]
device_release_driver_internal+0x44b/0x620 drivers/base/dd.c:1297
usb_driver_release_interface drivers/usb/core/driver.c:640 [inline]
usb_forced_unbind_intf+0x144/0x220 drivers/usb/core/driver.c:1133
usb_reset_device+0x439/0xa90 drivers/usb/core/hub.c:6403
if_usb_reset_device.isra.0+0x215/0x280 drivers/net/wireless/marvell/libertas/if_usb.c:400
if_usb_prog_firmware+0x63c/0x10c0 drivers/net/wireless/marvell/libertas/if_usb.c:877
lbs_fw_loaded drivers/net/wireless/marvell/libertas/firmware.c:23 [inline]
helper_firmware_cb drivers/net/wireless/marvell/libertas/firmware.c:80 [inline]
helper_firmware_cb+0x1f8/0x2e0 drivers/net/wireless/marvell/libertas/firmware.c:64
request_firmware_work_func+0x139/0x250 drivers/base/firmware_loader/main.c:1161
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x5b6/0x6c0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff892c7320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff892c7320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff892c7320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/2908:
#0: ffff8881123fe0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
4 locks held by udevd/5192:
3 locks held by kworker/0:4/5233:
3 locks held by kworker/1:5/10878:
#0: ffff888100080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
#1: ffffc90016497d10 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
#2: ffff88814573d160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff88814573d160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline]
#2: ffff88814573d160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xa4/0x620 drivers/base/dd.c:1294
3 locks held by kworker/1:8/12237:
3 locks held by kworker/0:1/14373:
5 locks held by kworker/0:8/19369:
#0: ffff888106eaf548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
#1: ffffc90013447d10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
#2: ffff88810b752198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff88810b752198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1be/0x5060 drivers/usb/core/hub.c:5898
#3: ffff88811d13c198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#3: ffff88811d13c198 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9c0 drivers/usb/core/hub.c:2335
#4: ffff88814573d160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#4: ffff88814573d160 (&dev->mutex){....}-{4:4}, at: device_del+0xa0/0x9f0 drivers/base/core.c:3840
2 locks held by kworker/u8:0/21113:
#0: ffff888100089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
#1: ffffc90012d3fd10 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
4 locks held by kworker/1:7/23200:

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.16.0-syzkaller-12288-g2b38afce25c4 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf0e/0x1260 kernel/hung_task.c:491
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x5b6/0x6c0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5219 Comm: kworker/1:4 Not tainted 6.16.0-syzkaller-12288-g2b38afce25c4 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:407
Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d e9 06 6b 66 04 e8 41 85 02 ff eb a0 e8 ca 85 02
RSP: 0018:ffffc9000233f700 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: ffffffff82d9a765 RDI: ffffffff93b7f160
RBP: ffffffff93b7f120 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff93b7f120 R15: ffffffff93b7f3e0
FS: 0000000000000000(0000) GS:ffff888268ffc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555908fc4a8 CR3: 000000014b144000 CR4: 00000000003506f0
Call Trace:
<TASK>
serial_out drivers/tty/serial/8250/8250.h:142 [inline]
serial8250_clear_IER+0x9b/0xc0 drivers/tty/serial/8250/8250_port.c:713
serial8250_console_write+0x255/0x1890 drivers/tty/serial/8250/8250_port.c:3361
console_emit_next_record kernel/printk/printk.c:3138 [inline]
console_flush_all+0x7fe/0xc60 kernel/printk/printk.c:3226
__console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
_printk+0xc7/0x100 kernel/printk/printk.c:2475
legacy_dvb_usb_read_remote_control+0x40b/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:124
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x5b6/0x6c0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup