syzbot

INFO: task udevd:4370 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:27040 pid:4370  ppid:3638   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 device_lock include/linux/device.h:837 [inline]
 uevent_show+0x16c/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+0x49b/0xd50 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+0x434/0x920 fs/read_write.c:470
 ksys_read+0x143/0x240 fs/read_write.c:613
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcd86aa7407
RSP: 002b:00007ffd58b065e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fcd871f2880 RCX: 00007fcd86aa7407
RDX: 0000000000001000 RSI: 0000555a4d26e2f0 RDI: 0000000000000008
RBP: 00007fcd86befff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007fcd86befea0 R14: 0000000000000000 R15: 0000555a4d2258a0
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2b570 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2bd90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2abe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by kworker/u4:3/46:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000b77d00 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by getty/4033:
 #0: ffff88814cb07098 (&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+0x41b/0x1380 drivers/tty/n_tty.c:2198
2 locks held by kworker/u4:5/4309:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004857d00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
4 locks held by udevd/4370:
 #0: ffff88802d354540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182
 #1: ffff88801c3ba088 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3b0 fs/kernfs/file.c:154
 #2: ffff88807fcd3578 (kn->active#5){.+.+}-{0:0}, at: kernfs_seq_start+0x71/0x3b0 fs/kernfs/file.c:155
 #3: ffff888073930190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
 #3: ffff888073930190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x16c/0x320 drivers/base/core.c:2669
5 locks held by kworker/1:27/4432:
2 locks held by dhcpcd/4492:
 #0: ffff8880455a2130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff8880455a2130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3248
 #1: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #1: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962
2 locks held by dhcpcd/4495:
 #0: ffff88802b038130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff88802b038130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3248
 #1: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #1: ffffffff8cb308b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x346/0x830 kernel/rcu/tree_exp.h:962
1 lock held by dhcpcd/4496:
 #0: ffff88802760c130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff88802760c130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3248
1 lock held by dhcpcd/4497:
 #0: ffff888024b92130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff888024b92130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3248
1 lock held by dhcpcd/4498:
 #0: ffff888024da8130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff888024da8130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3248
1 lock held by dhcpcd/4499:
 #0: ffff888024c30130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1756 [inline]
 #0: ffff888024c30130 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xce0 net/packet/af_packet.c:3248

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 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+0xeee/0xf30 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4432 Comm: kworker/1:27 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: usb_hub_wq hub_event
RIP: 0010:unwind_next_frame+0x6dd/0x20b0 arch/x86/kernel/unwind_orc.c:471
Code: 00 00 44 89 f9 80 e1 07 38 c1 0f 8c 75 02 00 00 be 02 00 00 00 49 89 d6 4c 89 ff e8 4d 87 98 00 e9 3b 18 00 00 48 8b 44 24 50 <42> 80 3c 28 00 4c 8b 74 24 58 74 08 4c 89 f7 e8 6f 86 98 00 49 8b
RSP: 0018:ffffc900001e0410 EFLAGS: 00000097
RAX: 1ffff9200003c0a4 RBX: ffffc900001e04e8 RCX: ffffffff8e5aca88
RDX: ffffffff8ee060ae RSI: ffffffff8e5aca40 RDI: 0000000000000001
RBP: ffffffff8ee06118 R08: 0000000000000012 R09: 000000000000001f
R10: fffff5200003c0a9 R11: 1ffff9200003c0a7 R12: ffffffff8ee06114
R13: dffffc0000000000 R14: ffffffff8e5aca84 R15: 0000000000000005
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f578e9d5fa4 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
 dummy_timer+0x801/0x31b0 drivers/usb/gadget/udc/dummy_hcd.c:1988
 __run_hrtimer kernel/time/hrtimer.c:1752 [inline]
 __hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1816
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1833
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:stack_trace_consume_entry+0x10e/0x270 kernel/stacktrace.c:94
Code: 4c 89 f8 48 c1 e8 03 80 3c 10 00 74 1a 4c 89 ff 48 89 f3 49 89 d4 4c 89 c5 e8 0e 3a 61 00 49 89 e8 4c 89 e2 48 89 de 49 89 37 <41> 8b 18 41 0f b6 44 15 00 84 c0 0f 85 2f 01 00 00 41 3b 1e 0f 92
RSP: 0018:ffffc900034a67d8 EFLAGS: 00000246
RAX: 1ffff92000694d30 RBX: ffffc900034a6970 RCX: 0000000080000000
RDX: dffffc0000000000 RSI: ffffffff81b8e020 RDI: ffffc900034a68e0
RBP: 1ffff92000694d1e R08: ffffc900034a68f0 R09: 0000000000000002
R10: fffff52000694d11 R11: 1ffff92000694d0f R12: 0000000000000000
R13: 1ffff92000694d1d R14: ffffc900034a68e8 R15: ffffc900034a6980
 arch_stack_walk+0x100/0x140 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:383
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:936 [inline]
 __kmalloc+0xb0/0x240 mm/slab_common.c:949
 kmalloc include/linux/slab.h:568 [inline]
 usb_alloc_urb+0x3f/0x140 drivers/usb/core/urb.c:75
 ath6kl_usb_post_recv_transfers+0x24f/0x6f0 drivers/net/wireless/ath/ath6kl/usb.c:432
 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+0x66/0x280 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+0x1ce/0x10c0 drivers/net/wireless/ath/ath6kl/core.c:97
 ath6kl_usb_probe+0x144a/0x1540 drivers/net/wireless/ath/ath6kl/usb.c:1168
 usb_probe_interface+0x5a0/0xaf0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2aa/0xc70 drivers/base/dd.c:639
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:785
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:815
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:943
 bus_for_each_drv+0x175/0x200 drivers/base/bus.c:429
 __device_attach+0x29b/0x460 drivers/base/dd.c:1015
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3697
 usb_set_configuration+0x1991/0x1fd0 drivers/usb/core/message.c:2165
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x139/0x270 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2aa/0xc70 drivers/base/dd.c:639
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:785
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:815
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:943
 bus_for_each_drv+0x175/0x200 drivers/base/bus.c:429
 __device_attach+0x29b/0x460 drivers/base/dd.c:1015
 bus_probe_device+0xbc/0x1e0 drivers/base/bus.c:489
 device_add+0xa00/0xfb0 drivers/base/core.c:3697
 usb_new_device+0xd4d/0x1620 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+0x2d5e/0x54e0 drivers/usb/core/hub.c:5899
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>