INFO: task syz.4.4464:22701 blocked for more than 143 seconds.
Not tainted syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.4464 state:D stack:23688 pid:22701 tgid:22700 ppid:17425 task_flags:0x400448 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_timeout+0x9a/0x270 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+0x2bf/0x5d0 kernel/sched/completion.c:153
io_wq_exit_workers io_uring/io-wq.c:1327 [inline]
io_wq_put_and_exit+0x316/0x650 io_uring/io-wq.c:1355
io_uring_clean_tctx+0x11f/0x1a0 io_uring/tctx.c:203
io_uring_cancel_generic+0x6ca/0x7d0 io_uring/io_uring.c:3327
io_uring_files_cancel include/linux/io_uring.h:19 [inline]
do_exit+0x345/0x2300 kernel/exit.c:912
do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f063f98f749
RSP: 002b:00007f06407ca038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: 0000000000004000 RBX: 00007f063fbe5fa0 RCX: 00007f063f98f749
RDX: 0000000000000000 RSI: 00000000000047ba RDI: 0000000000000006
RBP: 00007f063fa13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000028 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f063fbe6038 R14: 00007f063fbe5fa0 R15: 00007f063fd0fa28
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5595:
#0: ffff88814e39d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
5 locks held by kworker/0:10/16427:
#0: ffff888143e9b148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888143e9b148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000cb57ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000cb57ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff88814674d198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff88814674d198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff888028aa0518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3251 [inline]
#3: ffff888028aa0518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5463 [inline]
#3: ffff888028aa0518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#3: ffff888028aa0518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#3: ffff888028aa0518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20 drivers/usb/core/hub.c:5952
#4: ffff888027b38168 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
#4: ffff888027b38168 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#4: ffff888027b38168 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#4: ffff888027b38168 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20 drivers/usb/core/hub.c:5952
1 lock held by syz.3.4090/21277:
#0: ffffffff8df43040 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3820
2 locks held by iou-wrk-22701/22703:
5 locks held by kworker/u8:17/22823:
1 lock held by syz.9.5019/24847:
#0: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
2 locks held by dhcpcd/24853:
#0: ffff88807b22e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
#0: ffff88807b22e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3197
#1: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8df43178 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
1 lock held by dhcpcd/24854:
#0: ffff888079d5e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
#0: ffff888079d5e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3197
1 lock held by dhcpcd/24855:
#0: ffff88807f33e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1679 [inline]
#0: ffff88807f33e260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3197
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 22703 Comm: iou-wrk-22701 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:unwind_next_frame+0xc86/0x2390 arch/x86/kernel/unwind_orc.c:590
Code: e8 2f 2e b2 00 49 89 1f 48 8b 44 24 58 80 3c 28 00 48 8b 5c 24 70 4c 8b 6c 24 50 4c 8b 64 24 10 74 08 48 89 df e8 0a 2e b2 00 <4c> 89 23 ba 10 00 00 00 4c 89 ef 31 f6 e8 d8 2f b2 00 48 8b 14 24
RSP: 0018:ffffc9000487e758 EFLAGS: 00000246
RAX: 1ffff9200090fd0c RBX: ffffc9000487e860 RCX: 1ffff9200090fd01
RDX: ffffffff903e0206 RSI: 0000000000000002 RDI: ffffc9000487efa8
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff81738c45
R10: ffffc9000487e878 R11: ffffffff81ac2e10 R12: ffffc9000487efb0
R13: ffffc9000487e878 R14: ffffc9000487e828 R15: ffffc9000487e870
FS: 00007f06407ca6c0(0000) GS:ffff888126239000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe55282d70 CR3: 00000000306e2000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000318 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
slab_free_hook mm/slub.c:2504 [inline]
slab_free mm/slub.c:6642 [inline]
kmem_cache_free+0x4a2/0x690 mm/slub.c:6752
__bio_chain_endio block/bio.c:319 [inline]
bio_endio+0x43/0x8c0 block/bio.c:1655
blk_update_request+0x57e/0xe60 block/blk-mq.c:998
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1160
nullb_complete_cmd drivers/block/null_blk/main.c:1402 [inline]
null_handle_cmd drivers/block/null_blk/main.c:1454 [inline]
null_queue_rq+0xbfe/0xe30 drivers/block/null_blk/main.c:1693
null_queue_rqs+0x123/0x270 drivers/block/null_blk/main.c:1707
__blk_mq_flush_list block/blk-mq.c:2837 [inline]
blk_mq_dispatch_queue_requests+0x417/0x800 block/blk-mq.c:2882
blk_mq_flush_plug_list+0x432/0x550 block/blk-mq.c:2970
blk_add_rq_to_plug+0x175/0x450 block/blk-mq.c:1399
blk_mq_submit_bio+0x1a65/0x25b0 block/blk-mq.c:3222
__submit_bio+0x207/0x5a0 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x387/0xa50 block/blk-core.c:755
__blkdev_direct_IO+0x915/0xf90 block/fops.c:264
blkdev_direct_IO+0x1261/0x17e0 block/fops.c:441
blkdev_read_iter+0x23d/0x440 block/fops.c:843
io_iter_do_read io_uring/rw.c:837 [inline]
__io_read+0x70a/0x1500 io_uring/rw.c:954
io_read+0x4a/0x1c0 io_uring/rw.c:1034
__io_issue_sqe+0x181/0x4b0 io_uring/io_uring.c:1824
io_issue_sqe+0x165/0x1060 io_uring/io_uring.c:1847
io_wq_submit_work+0x6e9/0xb90 io_uring/io_uring.c:1959
io_worker_handle_work+0x7cd/0x1180 io_uring/io-wq.c:650
io_wq_worker+0x42f/0xeb0 io_uring/io-wq.c:704
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245