INFO: task hung in bus_remove_device (2)

Status: auto-obsoleted due to no activity on 2026/07/13 14:03
Subsystems: libertas
Labels: prio:high
[Documentation on labels]
First crash: 142d, last: 142d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
85d942fe assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ INFO: task hung in bus_remove_device (2) 2026/05/23 15:45 2026/05/23 15:45 2026/05/23 16:09 c69befb3
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in bus_remove_device kernel 1 1 771d 771d 0/29 auto-obsoleted due to no activity on 2024/10/23 12:04

Sample crash report:
INFO: task kworker/0:4:5235 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xeb1/0x4220 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 lbs_wait_for_firmware_load+0x11e/0x1e0 drivers/net/wireless/marvell/libertas/firmware.c:116
 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:657
 device_del+0x376/0x9b0 drivers/base/core.c:3880
 usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1478
 usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2345
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
5 locks held by kworker/0:0/9:
 #0: ffff888105ee4d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffffc9000009fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
 #2: ffff88810affb1e0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #2: ffff88810affb1e0 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
 #3: ffff88813cdca1e0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #3: ffff88813cdca1e0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
 #4: ffff88813f3001a8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #4: ffff88813f3001a8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
1 lock held by khungtaskd/29:
 #0: ffffffff896de760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff896de760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff896de760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
3 locks held by kworker/1:2/2760:
2 locks held by getty/2917:
 #0: ffff88811290d0a0 (&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+0x419/0x1500 drivers/tty/n_tty.c:2211
2 locks held by kworker/1:3/5201:
 #0: ffff88810006b148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffffc900034bfd18 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
3 locks held by kworker/1:4/5214:
 #0: ffff888105ee4d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffffc900034dfd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
 #2: ffff88810b35b1e0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #2: ffff88810b35b1e0 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
5 locks held by kworker/0:4/5235:
 #0: ffff888105ee4d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
 #1: ffffc9000345fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
 #2: ffff88810b39b1e0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #2: ffff88810b39b1e0 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
 #3: ffff88811ae351e0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #3: ffff88811ae351e0 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336
 #4: ffff88811c2a11a8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #4: ffff88811c2a11a8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1166 [inline]
 #4: ffff88811c2a11a8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1364
3 locks held by S10udev/8275:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x141/0x190 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xd25/0x1050 kernel/hung_task.c:515
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8275 Comm: udevadm Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:417
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <c3> cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 e9 eb 8f ec f9 cc
RSP: 0000:ffffc900152f7bd0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000027 RCX: ffffffff821ae2d3
RDX: 0000000000000000 RSI: 0000000000000fff RDI: ffff88810ba89d80
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000fff
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f90ae261880(0000) GS:ffff8882686c9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c57ea5e028 CR3: 000000011961a000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __nr_to_section+0xa3/0xe0 include/linux/mmzone.h:1972
 __pfn_to_section include/linux/mmzone.h:2114 [inline]
 pfn_valid include/linux/mmzone.h:2196 [inline]
 page_table_check_set+0x3b/0xa10 mm/page_table_check.c:105
 __page_table_check_ptes_set+0x1db/0x230 mm/page_table_check.c:215
 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline]
 set_ptes include/linux/pgtable.h:413 [inline]
 do_anonymous_page mm/memory.c:5317 [inline]
 do_pte_missing mm/memory.c:4475 [inline]
 handle_pte_fault mm/memory.c:6317 [inline]
 __handle_mm_fault+0x21df/0x2d60 mm/memory.c:6455
 handle_mm_fault+0x36d/0xa20 mm/memory.c:6624
 do_user_addr_fault+0x5ae/0x11d0 arch/x86/mm/fault.c:1334
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x66/0xc0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f90ae360d34
Code: 8d 34 19 49 39 d0 49 89 70 60 0f 95 c2 48 29 d8 48 83 c1 10 0f b6 d2 48 83 c8 01 48 c1 e2 02 48 09 da 48 83 ca 01 48 89 51 f8 <48> 89 46 08 48 89 cf 4c 89 e6 48 89 4c 24 08 e8 18 c7 ff ff 48 8b
RSP: 002b:00007ffec5aedbd0 EFLAGS: 00010202
RAX: 000000000001ffe1 RBX: 00000000000000f0 RCX: 000055c57ea5df40
RDX: 00000000000000f1 RSI: 000055c57ea5e020 RDI: 0000000000000000
RBP: fffffffffffffe98 R08: 00007f90ae499ac0 R09: 00000000000000f0
R10: 0000000000000004 R11: 000055c57ea5d000 R12: 00000000000000df
R13: 00000000000000f0 R14: 000000000000000d R15: 00007f90ae499b20
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/14 14:02 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 87117347a0e7 362d1323 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in bus_remove_device
* Struck through repros no longer work on HEAD.