INFO: task syz.3.12229:13674 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.12229 state:D stack:24184 pid:13674 tgid:13674 ppid:9245 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5520 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7270
__schedule_loop kernel/sched/core.c:7347 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7362
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7419
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
pipe_release+0x48/0x330 fs/pipe.c:812
__fput+0x418/0xa50 fs/file_table.c:512
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8c3739e159
RSP: 002b:00007f8c3774fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f8c37627da0 RCX: 00007f8c3739e159
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f8c37627da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f8c37627cb0 R11: 0000000000000246 R12: 00000000002d86df
R13: 00007f8c3762618c R14: 00000000002d86a5 R15: 00007f8c37626180
INFO: task syz.3.12229:13676 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.12229 state:D stack:25720 pid:13676 tgid:13674 ppid:9245 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5520 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7270
__schedule_loop kernel/sched/core.c:7347 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7362
__lock_sock+0x162/0x2c0 net/core/sock.c:3235
lock_sock_nested+0xc7/0x100 net/core/sock.c:3848
lock_sock include/net/sock.h:1713 [inline]
tcp_splice_read+0x15d/0x950 net/ipv4/tcp.c:834
do_splice_read fs/splice.c:980 [inline]
splice_file_to_pipe+0x444/0x6b0 fs/splice.c:1290
do_splice+0x11c2/0x1970 fs/splice.c:1374
__do_splice fs/splice.c:1431 [inline]
__do_sys_splice fs/splice.c:1634 [inline]
__se_sys_splice+0x353/0x490 fs/splice.c:1616
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8c3739e159
RSP: 002b:00007f8c382fb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007f8c37626090 RCX: 00007f8c3739e159
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f8c37435024 R08: 000000007ffff000 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8c37626128 R14: 00007f8c37626090 R15: 00007f8c3774fa48
Showing all locks held in the system:
locks held by khungtaskd/33: 1, last CPU#0:
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6837
locks held by getty/5375: 2, on CPU#0:
#0: ffff8880284560a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/u8:1/1166: 3, on CPU#0:
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc9000f177c40 ((linkwatch_work).work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000f177c40 ((linkwatch_work).work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000f177c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc9000f177c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
locks held by kworker/0:7/9377: 3, on CPU#0:
#0: ffff888022ae1d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888022ae1d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888022ae1d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888022ae1d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc9000457fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000457fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000457fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc9000457fc40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffff88802963f1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802963f1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5912
locks held by syz.3.12229/13674: 1, on CPU#1:
#0: ffff888028196460 (&pipe->mutex){+.+.}-{4:4}, at: pipe_release+0x48/0x330 fs/pipe.c:812
locks held by syz.3.12229/13675: 2, last CPU#1:
#0: ffff8880353b5060 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff8880353b5060 (sk_lock-AF_INET){+.+.}-{0:0}, at: sk_stream_wait_memory+0x8d8/0xf80 net/core/stream.c:148
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.3.12229/13676: 2, on CPU#0:
#0: ffff888028196460 (&pipe->mutex){+.+.}-{4:4}, at: splice_file_to_pipe+0x3e/0x6b0 fs/splice.c:1287
#1: ffff8880353b5060 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#1: ffff8880353b5060 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_splice_read+0x15d/0x950 net/ipv4/tcp.c:834
locks held by syz.8.13410/16719: 1, last CPU#1:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:650 [inline]
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3587
locks held by syz.9.13413/16733: 1, on CPU#1:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3da/0x1e70 drivers/net/tun.c:3229
locks held by syz.7.13416/16740: 1, on CPU#1:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3da/0x1e70 drivers/net/tun.c:3229
locks held by syz.7.13416/16741: 1, on CPU#0:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x767/0xc00 net/core/rtnetlink.c:7138
locks held by syz.7.13416/16742: 1, on CPU#1:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x767/0xc00 net/core/rtnetlink.c:7138
locks held by syz.7.13416/16743: 1, on CPU#0:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x767/0xc00 net/core/rtnetlink.c:7138
locks held by syz.7.13416/16744: 1, on CPU#1:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x767/0xc00 net/core/rtnetlink.c:7138
locks held by syz.1.13419/16754: 1, last CPU#0:
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: find_lock_entries+0x12a/0xad0 mm/filemap.c:2188
locks held by syz.4.13424/16767: 1, on CPU#0:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3da/0x1e70 drivers/net/tun.c:3229
locks held by syz.4.13424/16768: 1, on CPU#0:
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff90250d80 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x2fb/0x1c50 net/ipv4/devinet.c:1120
locks held by syz.1.13425/16772: 2, last CPU#1:
#0: ffff88802851c378 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:619 [inline]
#0: ffff88802851c378 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline]
#0: ffff88802851c378 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8ed5c6e0 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.1.13425/16773: 1, last CPU#0:
#0: ffffffff8f4ef8f8 (tomoyo_ss){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:198 [inline]
#0: ffffffff8f4ef8f8 (tomoyo_ss){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:305 [inline]
#0: ffffffff8f4ef8f8 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_read_lock security/tomoyo/common.h:1112 [inline]
#0: ffffffff8f4ef8f8 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_path_number_perm+0x219/0x5f0 security/tomoyo/file.c:727
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 33 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 16719 Comm: syz.8.13410 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:chain_hlock_class_idx kernel/locking/lockdep.c:438 [inline]
RIP: 0010:remove_class_from_lock_chain kernel/locking/lockdep.c:6260 [inline]
RIP: 0010:remove_class_from_lock_chains kernel/locking/lockdep.c:6298 [inline]
RIP: 0010:zap_class+0x115/0x330 kernel/locking/lockdep.c:6343
Code: 74 b5 49 83 c5 f8 74 af 45 8b 75 00 41 f6 c6 fc 74 e7 41 c1 ee 08 4a 8d 1c 75 d0 14 9b 93 49 81 fe 00 00 50 00 73 2c 0f b7 03 <25> ff 1f 00 00 49 39 c7 74 30 49 ff c6 41 8b 45 00 89 c1 c1 e9 08
RSP: 0018:ffffc90005ebf920 EFLAGS: 00000087
RAX: 0000000000000621 RBX: ffffffff939d5d88 RCX: 00000000000ba236
RDX: ffffffff94961518 RSI: ffffffff94485da8 RDI: ffffffff94485e70
RBP: ffffffff949a1970 R08: da00000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8ed5c6e0 R12: 000000000001e160
R13: ffffffff94a2f3b0 R14: 000000000001245c R15: 0000000000001102
FS: 0000555583b84500(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000314030 CR3: 000000005feb0000 CR4: 00000000003526f0
DR0: 000000000000000c DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
__lockdep_free_key_range kernel/locking/lockdep.c:6469 [inline]
lockdep_unregister_key+0x1c3/0x350 kernel/locking/lockdep.c:6671
qdisc_lock_uninit include/net/pkt_sched.h:333 [inline]
__qdisc_destroy+0x1ab/0x470 net/sched/sch_generic.c:1124
netdev_for_each_tx_queue include/linux/netdevice.h:2749 [inline]
dev_shutdown+0x92/0x450 net/sched/sch_generic.c:1512
unregister_netdevice_many_notify+0x11f4/0x2140 net/core/dev.c:12505
unregister_netdevice_many net/core/dev.c:12589 [inline]
unregister_netdevice_queue+0x2f5/0x340 net/core/dev.c:12390
unregister_netdevice include/linux/netdevice.h:3487 [inline]
__tun_detach+0x1074/0x1900 drivers/net/tun.c:637
tun_detach drivers/net/tun.c:653 [inline]
tun_chr_close+0x10a/0x1c0 drivers/net/tun.c:3587
__fput+0x418/0xa50 fs/file_table.c:512
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f516659e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f516694fba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f5166827da0 RCX: 00007f516659e159
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f5166827da0 R08: 00007f5166826038 R09: 0000000000000000
R10: 00000000005eaf7c R11: 0000000000000246 R12: 00000000002fddb1
R13: 00007f516682609c R14: 00000000002fdb6b R15: 00007f5166826090