INFO: task syz-executor:11409 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc5-syzkaller-00275-gbec6f00f120e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:17576 pid:11409 tgid:11409 ppid:1      task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216
 __writeback_inodes_sb_nr+0x1f6/0x250 fs/fs-writeback.c:2747
 sync_filesystem+0xa3/0x230 fs/sync.c:54
 generic_shutdown_super+0x6f/0x2c0 fs/super.c:621
 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2620
 deactivate_locked_super+0xb9/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1431
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7242f8fc97
RSP: 002b:00007ffcbf89b638 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f724301089d RCX: 00007f7242f8fc97
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcbf89b6f0
RBP: 00007ffcbf89b6f0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffcbf89c780
R13: 00007f724301089d R14: 0000000000088c4a R15: 00007ffcbf89c7c0
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
 #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998
3 locks held by kworker/u8:1/13:
 #0: ffff88814ce76148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88814ce76148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc90000127c60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000127c60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4198
1 lock held by khungtaskd/31:
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
3 locks held by kworker/1:1/48:
 #0: ffff88801a080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc90000b97c60 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000b97c60 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
2 locks held by kworker/u8:4/68:
 #0: ffff88801cafe148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801cafe148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc9000159fc60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000159fc60 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
2 locks held by kworker/u8:6/1554:
5 locks held by kworker/u8:7/3514:
 #0: ffff88801aef3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801aef3948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc9000c537c60 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000c537c60 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffffffff8f2d5c10 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0x145/0xbd0 net/core/net_namespace.c:608
 #3: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: cleanup_net+0x611/0xbd0 net/core/net_namespace.c:644
 #4: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #4: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998
2 locks held by getty/5576:
 #0: ffff88814d51b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/1:8/8399:
 #0: ffff88801a080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc90003e6fc60 ((work_completion)(&(&devlink->rwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90003e6fc60 ((work_completion)(&(&devlink->rwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #2: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998
2 locks held by kworker/u8:10/9580:
1 lock held by syz-executor/11409:
 #0: ffff88805a8a60e0 (&type->s_umount_key#65){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88805a8a60e0 (&type->s_umount_key#65){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88805a8a60e0 (&type->s_umount_key#65){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
1 lock held by syz-executor/15601:
 #0: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4064
2 locks held by syz-executor/15963:
 #0: ffffffff8f7de0a0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8f7de0a0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8f7de0a0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8f2e2748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4064
1 lock held by dhcpcd/16017:
 #0: ffff888062640258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1651 [inline]
 #0: ffff888062640258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3252
1 lock held by dhcpcd/16018:
 #0: ffff8880511d0208 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #0: ffff8880511d0208 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline]
 #0: ffff8880511d0208 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1391

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc5-syzkaller-00275-gbec6f00f120e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 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:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 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: 3514 Comm: kworker/u8:7 Not tainted 6.15.0-rc5-syzkaller-00275-gbec6f00f120e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: netns cleanup_net
RIP: 0010:delay_tsc+0x5b/0xc0 arch/x86/lib/delay.c:79
Code: 90 49 89 d7 49 c1 e7 20 49 09 c7 4d 29 f7 49 39 df 73 53 bf 01 00 00 00 e8 32 e6 42 f6 65 8b 05 9b 17 24 07 85 c0 74 1c f3 90 <bf> 01 00 00 00 e8 6b e4 42 f6 e8 e6 38 01 00 39 c5 75 0e 0f 01 f9
RSP: 0018:ffffc9000c537150 EFLAGS: 00000006
RAX: 0000000000000203 RBX: 0000000000000899 RCX: 0000000000000200
RDX: 0000000000000173 RSI: ffffffff8bc0ff00 RDI: 00000000ffffffff
RBP: 0000000000000001 R08: ffff888024140237 R09: 1ffff11004828046
R10: dffffc0000000000 R11: ffffffff8b4de840 R12: 1ffffffff3362f82
R13: 00000000ffffffff R14: 00000173ba7ccb97 R15: 0000000000000706
FS:  0000000000000000(0000) GS:ffff888126200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff8136cf98 CR3: 00000000230e2000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 udelay include/asm-generic/delay.h:62 [inline]
 wait_for_lsr+0x160/0x2f0 drivers/tty/serial/8250/8250_port.c:2104
 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3348 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3371 [inline]
 serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3456
 console_emit_next_record kernel/printk/printk.c:3138 [inline]
 console_flush_all+0x725/0xc40 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
 _printk+0xcf/0x120 kernel/printk/printk.c:2475
 br_set_state+0x475/0x710 net/bridge/br_stp.c:57
 br_stp_disable_port+0x76/0x1d0 net/bridge/br_stp_if.c:106
 del_nbp+0x141/0xa60 net/bridge/br_if.c:343
 br_dev_delete+0x6e/0x100 net/bridge/br_if.c:386
 br_net_exit_batch_rtnl+0xfc/0x1a0 net/bridge/br.c:376
 cleanup_net+0x664/0xbd0 net/core/net_namespace.c:647
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>