INFO: task syz.4.192:8219 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.192       state:D stack:27944 pid:8219  tgid:8206  ppid:7539   task_flags:0x400040 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 rwsem_down_write_slowpath+0xedd/0x1420 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+0x1e2/0x220 kernel/locking/rwsem.c:1694
 inode_lock_nested include/linux/fs.h:902 [inline]
 do_unlinkat+0x26c/0x7b0 fs/namei.c:4595
 __do_sys_unlink fs/namei.c:4654 [inline]
 __se_sys_unlink fs/namei.c:4652 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4652
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fba8498e169
RSP: 002b:00007fba85748038 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007fba84bb6160 RCX: 00007fba8498e169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000200
RBP: 00007fba84a10a68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fba84bb6160 R15: 00007ffcf0a556e8
 </TASK>
INFO: task syz.4.192:8221 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.192       state:D stack:27624 pid:8221  tgid:8206  ppid:7539   task_flags:0x400040 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 rwsem_down_read_slowpath kernel/locking/rwsem.c:1084 [inline]
 __down_read_common kernel/locking/rwsem.c:1248 [inline]
 __down_read kernel/locking/rwsem.c:1261 [inline]
 down_read+0x6ff/0xa50 kernel/locking/rwsem.c:1526
 inode_lock_shared include/linux/fs.h:877 [inline]
 lookup_slow+0x45/0x70 fs/namei.c:1823
 walk_component fs/namei.c:2128 [inline]
 link_path_walk+0x969/0xeb0 fs/namei.c:2493
 path_openat+0x26d/0x35d0 fs/namei.c:4000
 do_filp_open+0x284/0x4e0 fs/namei.c:4031
 do_sys_openat2+0x12b/0x1d0 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+0x249/0x2a0 fs/open.c:1455
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fba8498e169
RSP: 002b:00007fba81ff2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fba84bb6320 RCX: 00007fba8498e169
RDX: 0000000000000042 RSI: 0000200000001800 RDI: ffffffffffffff9c
RBP: 00007fba84a10a68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fba84bb6320 R15: 00007ffcf0a556e8
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8ed43438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #0: ffffffff8ed43438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x454/0x830 kernel/rcu/tree_exp.h:998
1 lock held by khungtaskd/31:
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x30/0x180 kernel/locking/lockdep.c:6764
3 locks held by kworker/u8:6/1154:
 #0: ffff8880315e0148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff8880315e0148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc90003dbfc60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90003dbfc60 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffffffff900eb2c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #2: ffffffff900eb2c8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x110/0x16a0 net/ipv6/addrconf.c:4195
3 locks held by kworker/u8:8/2980:
 #0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc9000bab7c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000bab7c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffffffff900eb2c8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
2 locks held by dhcpcd/5496:
 #0: ffffffff900cfd48 (vlan_ioctl_mutex){+.+.}-{4:4}, at: sock_ioctl+0x6d1/0x900 net/socket.c:1273
 #1: ffffffff900eb2c8 (rtnl_mutex){+.+.}-{4:4}, at: vlan_ioctl_handler+0x118/0xa20 net/8021q/vlan.c:554
2 locks held by getty/5584:
 #0: ffff888031dbe0a0 (&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+0x5bb/0x1700 drivers/tty/n_tty.c:2222
5 locks held by syz.4.192/8207:
 #0: ffff88805d7ba420 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:556
 #1: ffff888052dd9810 (&sb->s_type->i_mutex_key#28/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #1: ffff888052dd9810 (&sb->s_type->i_mutex_key#28/1){+.+.}-{4:4}, at: filename_create+0x266/0x490 fs/namei.c:4097
 #2: ffff888052dd9bf8 (&inode->ei_update_lock){+.+.}-{4:4}, at: __bch2_create+0x359/0xf40 fs/bcachefs/fs.c:550
 #3: ffff888043184228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline]
 #3: ffff888043184228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline]
 #3: ffff888043184228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0x9a/0x1a0 fs/bcachefs/btree_iter.c:3199
 #4: ffff8880431a6590 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x68a/0x16c0 fs/bcachefs/btree_update_interior.c:1179
2 locks held by syz.4.192/8219:
 #0: ffff88805d7ba420 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:556
 #1: ffff888052dd9810 (&sb->s_type->i_mutex_key#28/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #1: ffff888052dd9810 (&sb->s_type->i_mutex_key#28/1){+.+.}-{4:4}, at: do_unlinkat+0x26c/0x7b0 fs/namei.c:4595
1 lock held by syz.4.192/8221:
 #0: ffff888052dd9810 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:877 [inline]
 #0: ffff888052dd9810 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: lookup_slow+0x45/0x70 fs/namei.c:1823
2 locks held by bch-copygc/loop/8216:
1 lock held by syz-executor/9233:
 #0: ffff888029b900e0 (&type->s_umount_key#63){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff888029b900e0 (&type->s_umount_key#63){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff888029b900e0 (&type->s_umount_key#63){+.+.}-{4:4}, at: deactivate_super+0xb5/0xf0 fs/super.c:505
1 lock held by syz-executor/9511:
 #0: ffffffff900eb2c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff900eb2c8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x406/0x1c40 net/ipv4/devinet.c:979
8 locks held by syz-executor/9650:
 #0: ffff888035eb2420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3041 [inline]
 #0: ffff888035eb2420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x23f/0xd10 fs/read_write.c:680
 #1: ffff8880278c0c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e2/0x510 fs/kernfs/file.c:325
 #2: ffff8880284001e8 (kn->active#49){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x206/0x510 fs/kernfs/file.c:326
 #3: ffffffff8f984c68 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xfe/0x490 drivers/net/netdevsim/bus.c:216
 #4: ffff888080eaa0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #4: ffff888080eaa0e8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1095 [inline]
 #4: ffff888080eaa0e8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xce/0x7c0 drivers/base/dd.c:1293
 #5: ffff888055f62250 (&devlink->lock_key#19){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1675
 #6: ffffffff900eb2c8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x10d/0x690 drivers/net/netdevsim/netdev.c:1059
 #7: ffffffff8ed43438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #7: ffffffff8ed43438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x454/0x830 kernel/rcu/tree_exp.h:998

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x4ab/0x4e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 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+0x1058/0x10a0 kernel/hung_task.c:437
 kthread+0x7b7/0x940 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: 9511 Comm: syz-executor Not tainted 6.15.0-rc2-syzkaller-00400-g3088d26962e8 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:io_serial_out+0x7e/0xc0 drivers/tty/serial/8250/8250_port.c:416
Code: fc 89 e9 41 d3 e7 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 5c b9 9b fc 44 03 3b 44 89 f0 44 89 fa ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc 89 e9 80 e1 07 38 c1 7c a7
RSP: 0018:ffffc9000419dd90 EFLAGS: 00000002
RAX: 0000000000000034 RBX: ffffffff9aa47960 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000000 R08: ffffffff858eb02b R09: 1ffff11004ad8046
R10: dffffc0000000000 R11: ffffffff858eafe0 R12: dffffc0000000000
R13: 0000000000000034 R14: 0000000000000034 R15: 00000000000003f8
FS:  0000555591f07500(0000) GS:ffff8881250cf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555571167688 CR3: 0000000080824000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
 serial8250_console_write+0x1434/0x1e00 drivers/tty/serial/8250/8250_port.c:3456
 console_emit_next_record kernel/printk/printk.c:3138 [inline]
 console_flush_all+0x86b/0xec0 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0x151/0x3b0 kernel/printk/printk.c:3325
 vprintk_emit+0x761/0xa40 kernel/printk/printk.c:2450
 dev_vprintk_emit+0x358/0x420 drivers/base/core.c:4891
 dev_printk_emit+0xdf/0x130 drivers/base/core.c:4902
 __netdev_printk+0x3e0/0x4d0 net/core/dev.c:12403
 netdev_info+0x12d/0x180 net/core/dev.c:12458
 nsim_udp_tunnel_set_port+0x2b5/0x460 drivers/net/netdevsim/udp_tunnels.c:34
 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline]
 udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:246 [inline]
 __udp_tunnel_nic_device_sync+0xa83/0x13b0 net/ipv4/udp_tunnel_nic.c:289
 udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:312 [inline]
 __udp_tunnel_nic_add_port+0xc45/0xf10 net/ipv4/udp_tunnel_nic.c:531
 udp_tunnel_nic_add_port include/net/udp_tunnel.h:350 [inline]
 udp_tunnel_notify_add_rx_port+0x30c/0x4d0 net/ipv4/udp_tunnel_core.c:128
 geneve_socket_create drivers/net/geneve.c:612 [inline]
 geneve_sock_add+0x698/0xc40 drivers/net/geneve.c:687
 geneve_open+0xe3/0x160 drivers/net/geneve.c:729
 __dev_open+0x484/0x900 net/core/dev.c:1629
 __dev_change_flags+0x1e4/0x700 net/core/dev.c:9366
 netif_change_flags+0x8b/0x1a0 net/core/dev.c:9429
 do_setlink+0xee3/0x4390 net/core/rtnetlink.c:3152
 rtnl_changelink net/core/rtnetlink.c:3769 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3928 [inline]
 rtnl_newlink+0x17e2/0x1fe0 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x80f/0xd70 net/core/rtnetlink.c:6955
 netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:727
 __sys_sendto+0x365/0x4c0 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2183
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4dccf8fffc
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffcdc165790 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f4dcdce4620 RCX: 00007f4dccf8fffc
RDX: 000000000000002c RSI: 00007f4dcdce4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffcdc1657e4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f4dcdce4670 R15: 0000000000000000
 </TASK>