syzbot

INFO: task syz-executor:6092 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22216 pid:6092  tgid:6092  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x16ec/0x5620 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 percpu_rwsem_wait+0x317/0x480 kernel/locking/percpu-rwsem.c:164
 __percpu_down_read+0xfc/0x140 kernel/locking/percpu-rwsem.c:180
 __percpu_down_read+0xfc/0x140 kernel/locking/percpu-rwsem.c:180
 percpu_down_read_internal include/linux/percpu-rwsem.h:67 [inline]
 percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
 __sb_start_write include/linux/fs/super.h:19 [inline]
 sb_start_write+0x18e/0x1c0 include/linux/fs/super.h:125
 mnt_want_write+0x41/0x90 fs/namespace.c:493
 filename_unlinkat+0x148/0x610 fs/namei.c:5545
 __do_sys_unlink fs/namei.c:5603 [inline]
 __se_sys_unlink+0x2e/0x140 fs/namei.c:5600
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd03b7dbf47
RSP: 002b:00007ffd8be2b0c8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd03b7dbf47
RDX: 00007ffd8be2b0f0 RSI: 00007ffd8be2b180 RDI: 00007ffd8be2b180
RBP: 00007ffd8be2b180 R08: 00007ffd8be2c180 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd8be2c270
R13: 00007fd03b8721ca R14: 000000000002aabf R15: 00007ffd8be2e430
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/1:0/31:
 #0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
 #0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
 #1: ffffc90000a5fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
 #1: ffffc90000a5fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
 #2: ffff888064789280 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490
1 lock held by khungtaskd/37:
 #0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8dfc8000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:11/1430:
 #0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
 #0: ffff88801b290938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
 #1: ffffc900067f7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
 #1: ffffc900067f7c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
 #2: ffffffff8f341620 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:673
 #3: ffff8880635c2160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
 #3: ffff8880635c2160 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline]
 #3: ffff8880635c2160 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420 net/devlink/core.c:557
 #4: ffff88803196e310 (&devlink->lock_key#12){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline]
 #4: ffff88803196e310 (&devlink->lock_key#12){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline]
 #4: ffff88803196e310 (&devlink->lock_key#12){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420 net/devlink/core.c:557
 #5: ffffffff8dfce1b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
2 locks held by getty/5359:
 #0: ffff88803616b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
3 locks held by kworker/1:5/5724:
 #0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3289 [inline]
 #0: ffff88801a037938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3397
 #1: ffffc9000582fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3290 [inline]
 #1: ffffc9000582fc40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3397
 #2: ffff8880612ac280 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490
1 lock held by syz-executor/6092:
 #0: ffff888065180480 (sb_writers#31){++++}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
1 lock held by syz-executor/6838:
 #0: ffff888041f8a0d0 (&type->s_umount_key#78){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888041f8a0d0 (&type->s_umount_key#78){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff888041f8a0d0 (&type->s_umount_key#78){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
12 locks held by kworker/u8:17/7516:
2 locks held by syz-executor/7676:
 #0: ffff8880400e4480 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
 #1: ffff888061d96c18 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline]
 #1: ffff888061d96c18 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2914 [inline]
 #1: ffff888061d96c18 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2938 [inline]
 #1: ffff888061d96c18 (&type->i_mutex_dir_key#5/1){+.+.}-{4:4}, at: filename_rmdir+0x1cd/0x520 fs/namei.c:5414
1 lock held by syz-executor/7902:
 #0: ffffffff8f350378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f350378 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x65f/0xe30 net/ipv6/addrconf.c:5039
1 lock held by syz-executor/8018:
 #0: ffffffff8f350378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f350378 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978
1 lock held by syz-executor/8243:
1 lock held by dhcpcd-run-hook/8315:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [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+0xfd3/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7516 Comm: kworker/u8:17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:__bfs kernel/locking/lockdep.c:1815 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline]
RIP: 0010:__lock_acquire+0x197b/0x2cf0 kernel/locking/lockdep.c:5237
Code: 13 25 ff 0f 00 00 39 05 7f 06 d1 11 73 06 89 05 77 06 d1 11 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 f0 52 e9
RSP: 0018:ffffc90005fb6148 EFLAGS: 00000006
RAX: ffffffff9610d658 RBX: 0000000000000101 RCX: 0000000000000002
RDX: ffffffff95f5cae8 RSI: ffff888030e52cc0 RDI: 0000000000000101
RBP: 66c79762eb0ac79a R08: ffffc90005fb6110 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff81a0a260 R12: ffffc90005fb61d8
R13: ffffffff9312d128 R14: ffff888030e51ec0 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888126287000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6c3fb5d368 CR3: 000000005e6de000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
 debug_object_deactivate+0x6c/0x3a0 lib/debugobjects.c:900
 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline]
 remove_hrtimer kernel/time/hrtimer.c:1190 [inline]
 hrtimer_try_to_cancel+0x34e/0x670 kernel/time/hrtimer.c:1527
 update_curr_dl_se+0x307/0x1260 kernel/sched/deadline.c:1482
 update_curr+0x1fa/0x4e0 kernel/sched/fair.c:1441
 dequeue_entity kernel/sched/fair.c:5652 [inline]
 dequeue_entities+0x1a8/0x39e0 kernel/sched/fair.c:7346
 dequeue_task_fair+0x200/0x660 kernel/sched/fair.c:7442
 sched_change_begin+0x3da/0x680 kernel/sched/core.c:11181
 class_sched_change_constructor kernel/sched/sched.h:4130 [inline]
 do_set_cpus_allowed+0x23/0x90 kernel/sched/core.c:2755
 migrate_disable_switch kernel/sched/core.c:2425 [inline]
 __schedule+0x1889/0x5620 kernel/sched/core.c:7045
 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7463
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x4b/0x3c0 kernel/locking/lockdep.c:5879
 rcu_lock_release include/linux/rcupdate.h:310 [inline]
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
 unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4906
 kmem_alloc_batch lib/debugobjects.c:371 [inline]
 fill_pool+0x156/0x580 lib/debugobjects.c:420
 debug_objects_fill_pool+0xcf/0x110 lib/debugobjects.c:752
 debug_object_activate+0x36/0x520 lib/debugobjects.c:841
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 __call_rcu_common kernel/rcu/tree.c:3116 [inline]
 call_rcu+0x43/0x890 kernel/rcu/tree.c:3251
 refdst_drop include/net/dst.h:272 [inline]
 skb_dst_drop include/net/dst.h:284 [inline]
 wg_xmit+0x621/0x1000 drivers/net/wireguard/device.c:199
 __netdev_start_xmit include/linux/netdevice.h:5368 [inline]
 netdev_start_xmit include/linux/netdevice.h:5377 [inline]
 xmit_one net/core/dev.c:3888 [inline]
 dev_hard_start_xmit+0x2df/0x860 net/core/dev.c:3904
 __dev_queue_xmit+0x1428/0x3900 net/core/dev.c:4870
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246
 dst_output include/net/dst.h:470 [inline]
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ndisc_send_skb+0xd0b/0x1670 net/ipv6/ndisc.c:512
 addrconf_dad_completed+0x6e3/0xe60 net/ipv6/addrconf.c:4372
 addrconf_dad_work+0xdc4/0x1680 include/linux/rwlock_rt.h:-1
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x388/0x470 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
 </TASK>