INFO: task syz.3.17:6050 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.17        state:D stack:28200 pid:6050  tgid:6012  ppid:5822   task_flags:0x400040 flags:0x00000004
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
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578
 inode_lock include/linux/fs.h:867 [inline]
 open_last_lookups fs/namei.c:3797 [inline]
 path_openat+0x8da/0x3830 fs/namei.c:4036
 do_filp_open+0x1fa/0x410 fs/namei.c:4066
 do_sys_openat2+0x121/0x1c0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1455
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fef3ad8e969
RSP: 002b:00007fef3bc9b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fef3afb6080 RCX: 00007fef3ad8e969
RDX: 000000000000275a RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007fef3ae10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fef3afb6080 R15: 00007ffdfff5b688
 </TASK>
INFO: task syz.3.17:6051 blocked for more than 144 seconds.
      Not tainted 6.15.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.17        state:D stack:28952 pid:6051  tgid:6012  ppid:5822   task_flags:0x400040 flags:0x00000004
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
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1694
 inode_lock_nested include/linux/fs.h:902 [inline]
 do_unlinkat+0x1bf/0x560 fs/namei.c:4630
 __do_sys_unlinkat fs/namei.c:4684 [inline]
 __se_sys_unlinkat fs/namei.c:4677 [inline]
 __x64_sys_unlinkat+0xd3/0xf0 fs/namei.c:4677
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fef3ad8e969
RSP: 002b:00007fef3bc7a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007fef3afb6160 RCX: 00007fef3ad8e969
RDX: 0000000000000000 RSI: 0000200000000c40 RDI: ffffffffffffff9c
RBP: 00007fef3ae10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fef3afb6160 R15: 00007ffdfff5b688
 </TASK>
INFO: task syz.3.17:6052 blocked for more than 144 seconds.
      Not tainted 6.15.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.17        state:D stack:28344 pid:6052  tgid:6012  ppid:5822   task_flags:0x400040 flags:0x00000004
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
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 rwsem_down_read_slowpath+0x552/0x880 kernel/locking/rwsem.c:1084
 __down_read_common kernel/locking/rwsem.c:1248 [inline]
 __down_read kernel/locking/rwsem.c:1261 [inline]
 down_read+0x98/0x2e0 kernel/locking/rwsem.c:1526
 inode_lock_shared include/linux/fs.h:877 [inline]
 open_last_lookups fs/namei.c:3799 [inline]
 path_openat+0x8cb/0x3830 fs/namei.c:4036
 do_filp_open+0x1fa/0x410 fs/namei.c:4066
 do_sys_openat2+0x121/0x1c0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1455
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fef3ad8e969
RSP: 002b:00007fef3bc59038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fef3afb6240 RCX: 00007fef3ad8e969
RDX: 0000000000000000 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007fef3ae10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000040 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fef3afb6240 R15: 00007ffdfff5b688
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
3 locks held by kworker/u8:0/12:
 #0: ffff88814cd42148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88814cd42148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319
 #1: ffffc90000117c60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90000117c60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319
 #2: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4195
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
2 locks held by dhcpcd/5485:
 #0: ffff88807e1246d0 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xcd/0xe70 net/netlink/af_netlink.c:2255
 #1: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6823
2 locks held by getty/5572:
 #0: ffff8880308ac0a0 (&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
2 locks held by syz-executor/5828:
 #0: ffff88807d6c20e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88807d6c20e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88807d6c20e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffffffff8df41200 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3774
1 lock held by udevd/5992:
4 locks held by syz.3.17/6013:
 #0: ffff888027482420 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
 #1: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #1: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: filename_create+0x1f9/0x470 fs/namei.c:4132
 #2: ffff888051984228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline]
 #2: ffff888051984228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline]
 #2: ffff888051984228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x806/0xda0 fs/bcachefs/btree_iter.c:3385
 #3: ffff8880519a6590 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x68f/0x14c0 fs/bcachefs/btree_update_interior.c:1179
2 locks held by syz.3.17/6050:
 #0: ffff888027482420 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
 #1: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: open_last_lookups fs/namei.c:3797 [inline]
 #1: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: path_openat+0x8da/0x3830 fs/namei.c:4036
2 locks held by syz.3.17/6051:
 #0: ffff888027482420 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
 #1: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #1: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: do_unlinkat+0x1bf/0x560 fs/namei.c:4630
1 lock held by syz.3.17/6052:
 #0: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:877 [inline]
 #0: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: open_last_lookups fs/namei.c:3799 [inline]
 #0: ffff88805d8108e0 (&sb->s_type->i_mutex_key#26){++++}-{4:4}, at: path_openat+0x8cb/0x3830 fs/namei.c:4036
2 locks held by bch-copygc/loop/6039:
1 lock held by syz-executor/6268:
 #0: ffff8880283b20e0 (&type->s_umount_key#51){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880283b20e0 (&type->s_umount_key#51){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880283b20e0 (&type->s_umount_key#51){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
1 lock held by syz-executor/8322:
 #0: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x5b7/0xd20 net/ipv6/addrconf.c:5028
3 locks held by syz-executor/8562:
 #0: ffffffff8ea7bd20 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8ea7bd20 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8ea7bd20 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
 #1: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #1: ffffffff8f2e1508 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4064
 #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

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
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: 5131 Comm: kworker/u9:1 Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: hci6 hci_cmd_timeout
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409
Code: e8 6e 4e 89 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 af 1d e9 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000fa97350 EFLAGS: 00000002
RAX: 1ffffffff3362b00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffffff99b15c10 R08: ffff8880243c8237 R09: 1ffff11004879046
R10: dffffc0000000000 R11: ffffffff85366f20 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b15980 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888126202000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4d5dd80178 CR3: 000000002fa04000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:137 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]
 wait_for_lsr+0x19e/0x2f0 drivers/tty/serial/8250/8250_port.c:2098
 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
 bt_err+0x10b/0x160 net/bluetooth/lib.c:296
 hci_cmd_timeout+0xff/0x1e0 net/bluetooth/hci_core.c:1457
 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>