INFO: task hung in usb_audio_probe

Status: upstream: reported on 2026/08/07 20:01
Reported-by: syzbot+e74e3e3eddd9f6e46420@syzkaller.appspotmail.com
First crash: 1d01h, last: 1d01h
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in usb_audio_probe (5) sound 1 483 89d 115d 29/29 fixed on 2026/05/21 07:49
upstream INFO: task hung in usb_audio_probe (2) sound 1 1 780d 780d 0/29 auto-obsoleted due to no activity on 2024/09/17 10:08
linux-5.15 INFO: task hung in usb_audio_probe 1 1 6d01h 6d01h 0/3 upstream: reported on 2026/08/02 20:10
upstream INFO: task hung in usb_audio_probe sound 1 1 1814d 1814d 0/29 auto-closed as invalid on 2021/11/18 21:08
upstream INFO: task hung in usb_audio_probe (4) sound 1 1 435d 435d 0/29 auto-obsoleted due to no activity on 2025/08/28 06:21
android-6-12 INFO: task hung in usb_audio_probe 1 syz, C 80 6d07h 144d 0/1 premoderation: reported C repro on 2026/03/17 07:22
linux-6.6 INFO: task hung in usb_audio_probe 1 11 84d 104d 0/2 auto-obsoleted due to no activity on 2026/07/25 19:52
upstream INFO: task hung in usb_audio_probe (3) sound 1 3 549d 668d 0/29 auto-obsoleted due to no activity on 2025/05/06 03:30

Sample crash report:
INFO: task kworker/0:2:129 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2     state:D stack:23808 pid:129   ppid:2      flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
 usb_audio_probe+0x3e7/0x1e70 sound/usb/card.c:812
 usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:1034
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3712
 usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:1034
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3712
 usb_new_device+0xa01/0x15e0 drivers/usb/core/hub.c:2659
 hub_port_connect drivers/usb/core/hub.c:5517 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
 port_event drivers/usb/core/hub.c:5817 [inline]
 hub_event+0x2b2f/0x5200 drivers/usb/core/hub.c:5899
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
INFO: task udevd:8258 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:23120 pid:8258  ppid:3639   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
 device_lock include/linux/device.h:885 [inline]
 uevent_show+0x16e/0x320 drivers/base/core.c:2669
 dev_attr_show+0x50/0xb0 drivers/base/core.c:2372
 sysfs_kf_seq_show+0x349/0x4b0 fs/sysfs/file.c:59
 seq_read_iter+0x460/0xc50 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2259 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x471/0x960 fs/read_write.c:470
 ksys_read+0x14d/0x260 fs/read_write.c:613
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f122d6a7407
RSP: 002b:00007ffe09a76a60 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f122de31880 RCX: 00007f122d6a7407
RDX: 0000000000001000 RSI: 000055b197797770 RDI: 0000000000000008
RBP: 00007f122d7efff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007f122d7efea0 R14: 0000000000000000 R15: 000055b197779fa0
 </TASK>
INFO: task syz.1.1139:8452 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1139      state:D stack:25680 pid:8452  ppid:4276   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
 snd_seq_midisynth_remove+0x68/0x4f0 sound/core/seq/seq_midi.c:459
 device_remove drivers/base/dd.c:549 [inline]
 __device_release_driver drivers/base/dd.c:1279 [inline]
 device_release_driver_internal+0x4cf/0x7c0 drivers/base/dd.c:1305
 bus_remove_device+0x2dd/0x400 drivers/base/bus.c:531
 device_del+0x63f/0xa80 drivers/base/core.c:3900
 snd_seq_device_dev_disconnect+0x39/0x40 sound/core/seq_device.c:182
 __snd_device_disconnect sound/core/device.c:63 [inline]
 snd_device_disconnect_all+0xcf/0x200 sound/core/device.c:215
 snd_card_disconnect+0x385/0x810 sound/core/init.c:538
 snd_card_free_when_closed+0x13/0x50 sound/core/init.c:630
 f_midi_unbind+0x99/0xf0 drivers/usb/gadget/function/f_midi.c:1335
 purge_configs_funcs+0x241/0x3a0 drivers/usb/gadget/configfs.c:1274
 configfs_composite_unbind+0xa0/0x1c0 drivers/usb/gadget/configfs.c:1453
 gadget_unbind_driver+0x1bb/0x3d0 drivers/usb/gadget/udc/core.c:1702
 device_remove drivers/base/dd.c:547 [inline]
 __device_release_driver drivers/base/dd.c:1279 [inline]
 device_release_driver_internal+0x47d/0x7c0 drivers/base/dd.c:1305
 driver_detach+0x1ef/0x2d0 drivers/base/dd.c:1368
 bus_remove_driver+0x11c/0x230 drivers/base/bus.c:679
 usb_gadget_unregister_driver+0x4a/0x70 drivers/usb/gadget/udc/core.c:1762
 unregister_gadget drivers/usb/gadget/configfs.c:253 [inline]
 gadget_dev_desc_UDC_store+0x174/0x2e0 drivers/usb/gadget/configfs.c:280
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x30b/0x400 fs/configfs/file.c:229
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x482/0x9a0 fs/read_write.c:584
 ksys_write+0x14d/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd83359e0d9
RSP: 002b:00007fd834496028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd833825fa0 RCX: 00007fd83359e0d9
RDX: 0000000000000001 RSI: 00002000000002c0 RDI: 0000000000000005
RBP: 00007fd833635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd833826038 R14: 00007fd833825fa0 R15: 00007ffe7e4a6f18
 </TASK>
INFO: task syz.1.1139:8457 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1139      state:D stack:28880 pid:8457  ppid:4276   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
 function_drop+0x30/0x140 drivers/usb/gadget/configfs.c:649
 client_drop_item fs/configfs/dir.c:962 [inline]
 configfs_rmdir+0x88e/0x980 fs/configfs/dir.c:1567
 vfs_rmdir+0x34e/0x4a0 fs/namei.c:4199
 do_rmdir+0x29a/0x5c0 fs/namei.c:4260
 __do_sys_rmdir fs/namei.c:4279 [inline]
 __se_sys_rmdir fs/namei.c:4277 [inline]
 __x64_sys_rmdir+0x45/0x50 fs/namei.c:4277
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd83359e0d9
RSP: 002b:00007fd834475028 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00007fd833826090 RCX: 00007fd83359e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000340
RBP: 00007fd833635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd833826128 R14: 00007fd833826090 R15: 00007ffe7e4a6f18
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
8 locks held by kworker/0:1/14:
 #0: ffff88801e694538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000137d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffff888027a5a190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #2: ffff888027a5a190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5845
 #3: ffff888054b95190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #3: ffff888054b95190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0xf8/0x8a0 drivers/usb/core/hub.c:2305
 #4: ffff888054b94118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #4: ffff888054b94118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1099 [inline]
 #4: ffff888054b94118 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb1/0x7c0 drivers/base/dd.c:1302
 #5: ffffffff8dd00708 (register_mutex#6){+.+.}-{3:3}, at: usb_audio_disconnect+0xd0/0x6f0 sound/usb/card.c:960
 #6: ffff8880296a2170 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #6: ffff8880296a2170 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1099 [inline]
 #6: ffff8880296a2170 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb1/0x7c0 drivers/base/dd.c:1302
 #7: ffffffff8dcc62c8 (register_mutex#7){+.+.}-{3:3}, at: snd_seq_midisynth_remove+0x68/0x4f0 sound/core/seq/seq_midi.c:459
1 lock held by khungtaskd/27:
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
6 locks held by kworker/0:2/129:
 #0: ffff88801e694538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90002db7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffff8880280f2190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #2: ffff8880280f2190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5845
 #3: ffff8880243c4190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #3: ffff8880243c4190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
 #4: ffff8880234a0118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #4: ffff8880234a0118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
 #5: ffffffff8dd00708 (register_mutex#6){+.+.}-{3:3}, at: usb_audio_probe+0x3e7/0x1e70 sound/usb/card.c:812
2 locks held by getty/4028:
 #0: ffff88814cb4a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
6 locks held by kworker/1:3/4262:
 #0: ffff88801e694538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003dc7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffff888028102190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #2: ffff888028102190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5845
 #3: ffff88807410a190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #3: ffff88807410a190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
 #4: ffff88807b215118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #4: ffff88807b215118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
 #5: ffffffff8dd00708 (register_mutex#6){+.+.}-{3:3}, at: usb_audio_probe+0x3e7/0x1e70 sound/usb/card.c:812
6 locks held by kworker/1:4/4286:
 #0: ffff88801e694538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003f17d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffff888144f5a190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #2: ffff888144f5a190 (&dev->mutex){....}-{3:3}, at: hub_event+0x178/0x5200 drivers/usb/core/hub.c:5845
 #3: ffff888059450190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #3: ffff888059450190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
 #4: ffff888059456118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #4: ffff888059456118 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
 #5: ffffffff8dd00708 (register_mutex#6){+.+.}-{3:3}, at: usb_audio_probe+0x3e7/0x1e70 sound/usb/card.c:812
3 locks held by kworker/1:7/4320:
 #0: ffff88802f40cd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004107d00 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x15/0x30 net/ipv6/addrconf.c:4679
2 locks held by kworker/u4:11/4413:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900047dfd00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
4 locks held by udevd/8258:
 #0: ffff888026713668 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
 #1: ffff88807b92f088 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x59/0x410 fs/kernfs/file.c:172
 #2: ffff888027d4f2c0 (kn->active#5){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888027d4f2c0 (kn->active#5){.+.+}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
 #3: ffff8880243c4190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #3: ffff8880243c4190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16e/0x320 drivers/base/core.c:2669
4 locks held by udevd/8291:
 #0: ffff8880277181c8 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
 #1: ffff8880786c0088 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x59/0x410 fs/kernfs/file.c:172
 #2: ffff8880458b2bd0 (kn->active#5){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff8880458b2bd0 (kn->active#5){.+.+}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
 #3: ffff88807410a190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #3: ffff88807410a190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16e/0x320 drivers/base/core.c:2669
4 locks held by udevd/8293:
 #0: ffff888051560b08 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x9d/0xc50 fs/seq_file.c:182
 #1: ffff888056f12888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x59/0x410 fs/kernfs/file.c:172
 #2: ffff8880325bda00 (kn->active#5){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff8880325bda00 (kn->active#5){.+.+}-{0:0}, at: kernfs_seq_start+0xae/0x410 fs/kernfs/file.c:173
 #3: ffff888059456118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #3: ffff888059456118 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16e/0x320 drivers/base/core.c:2669
8 locks held by syz.1.1139/8452:
 #0: ffff88807920e5e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2ae/0x360 fs/file.c:1038
 #1: ffff8881422b2460 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
 #2: ffff8880799d0688 (&buffer->mutex){+.+.}-{3:3}, at: configfs_write_iter+0x7d/0x400 fs/configfs/file.c:226
 #3: ffff88801fb02178 (&p->frag_sem){++++}-{3:3}, at: flush_write_buffer fs/configfs/file.c:205 [inline]
 #3: ffff88801fb02178 (&p->frag_sem){++++}-{3:3}, at: configfs_write_iter+0x20e/0x400 fs/configfs/file.c:229
 #4: ffff888055dd4310 (&gi->lock){+.+.}-{3:3}, at: gadget_dev_desc_UDC_store+0xed/0x2e0 drivers/usb/gadget/configfs.c:277
 #5: ffff88802678cdc0 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #5: ffff88802678cdc0 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1099 [inline]
 #5: ffff88802678cdc0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb1/0x7c0 drivers/base/dd.c:1302
 #6: ffff888055dd0170 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #6: ffff888055dd0170 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1099 [inline]
 #6: ffff888055dd0170 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb1/0x7c0 drivers/base/dd.c:1302
 #7: ffffffff8dcc62c8 (register_mutex#7){+.+.}-{3:3}, at: snd_seq_midisynth_remove+0x68/0x4f0 sound/core/seq/seq_midi.c:459
5 locks held by syz.1.1139/8457:
 #0: ffff8881422b2460 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
 #1: ffff888057bfb900 (&default_group_class[depth - 1]#2/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff888057bfb900 (&default_group_class[depth - 1]#2/1){+.+.}-{3:3}, at: do_rmdir+0x1b7/0x5c0 fs/namei.c:4247
 #2: ffff888057ad9590 (&sb->s_type->i_mutex_key#21){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #2: ffff888057ad9590 (&sb->s_type->i_mutex_key#21){++++}-{3:3}, at: vfs_rmdir+0xea/0x4a0 fs/namei.c:4188
 #3: ffffffff8d7b2f90 (gadget_subsys.su_mutex){+.+.}-{3:3}, at: configfs_rmdir+0x638/0x980 fs/configfs/dir.c:1556
 #4: ffff888055dd4310 (&gi->lock){+.+.}-{3:3}, at: function_drop+0x30/0x140 drivers/usb/gadget/configfs.c:649
2 locks held by syz.4.1224/8751:
 #0: ffff8881422b2460 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
 #1: ffff888057bfb900 (&default_group_class[depth - 1]#2/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
 #1: ffff888057bfb900 (&default_group_class[depth - 1]#2/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3884
1 lock held by syz.0.1254/8872:
 #0: ffff88802678cdc0 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #0: ffff88802678cdc0 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1099 [inline]
 #0: ffff88802678cdc0 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x432/0x6c0 drivers/base/dd.c:1219
2 locks held by kworker/0:12/9594:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003bcfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/u4:6/9632:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900046dfd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
1 lock held by syz.3.1514/9746:
 #0: ffff8880280f2190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #0: ffff8880280f2190 (&dev->mutex){....}-{3:3}, at: usbdev_open+0x14e/0x7a0 drivers/usb/core/devio.c:1052
2 locks held by syz-executor/9883:
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
 #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 57 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:60 [inline]
RIP: 0010:unwind_next_frame+0x1690/0x1fd0 arch/x86/kernel/unwind_orc.c:622
Code: f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 c6 49 9a 00 49 8b 06 4d 39 fc 0f 96 c1 4c 39 f8 0f 97 c2 20 ca 80 fa 01 75 7f <49> 8d 4f 08 4c 39 e1 76 76 48 39 c1 77 71 4c 3b 7c 24 68 77 6a 4c
RSP: 0018:ffffc900015875e0 EFLAGS: 00000246
RAX: ffffc90001588000 RBX: ffffc90001587688 RCX: 0000000000000001
RDX: ffffc90001587601 RSI: dffffc0000000000 RDI: ffffc90001587690
RBP: dffffc0000000000 R08: ffffc90001587b70 R09: ffffc900015876d8
R10: dffffc0000000000 R11: fffff520002b0edd R12: ffffc90001580000
R13: dffffc0000000000 R14: ffffc90001587698 R15: ffffc90001587b80
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffb117535c0 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xb6/0x200 mm/slub.c:3700
 skb_free_head net/core/skbuff.c:762 [inline]
 skb_release_data+0x5e9/0x7e0 net/core/skbuff.c:791
 skb_release_all net/core/skbuff.c:856 [inline]
 __kfree_skb net/core/skbuff.c:870 [inline]
 consume_skb+0xa2/0x100 net/core/skbuff.c:1035
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline]
 nsim_dev_trap_report_work+0x71f/0xa80 drivers/net/netdevsim/dev.c:851
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/07 20:01 linux-6.1.y e4f7d8be268e e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in usb_audio_probe
* Struck through repros no longer work on HEAD.