INFO: task syz.6.229:8826 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.229       state:D stack:25480 pid:8826  tgid:8825  ppid:7823   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7668
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1670 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked+0x1f88/0x25b0 kernel/locking/rtmutex.c:1787
 rt_mutex_slowlock+0xbd/0x180 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 rwbase_write_lock+0x14c/0x720 kernel/locking/rwbase_rt.c:251
 __super_lock fs/super.c:60 [inline]
 super_lock+0x289/0x3d0 fs/super.c:124
 user_get_super+0x57/0x110 fs/super.c:1050
 quotactl_block fs/quota/quota.c:889 [inline]
 __do_sys_quotactl fs/quota/quota.c:955 [inline]
 __se_sys_quotactl+0x53b/0x9f0 fs/quota/quota.c:917
 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: 0033:0x7f18afe9e159
RSP: 002b:00007f18ae0f6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f18b0125fa0 RCX: 00007f18afe9e159
RDX: 0000000000000002 RSI: 00002000000000c0 RDI: 0000000080000201
RBP: 00007f18aff3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000200 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f18b0126038 R14: 00007f18b0125fa0 R15: 00007fffb85773a8
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/38: 1, last CPU#0:
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:3/56: 7, last CPU#1:
 #0: ffff88801aeb0938
 ((wq_completion)netns){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 ((wq_completion)netns){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc9000122fc40 (net_cleanup_work){+.+.}-{0:0}
, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
, at: process_one_work kernel/workqueue.c:3361 [inline]
, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffffffff8f5c7140 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:677
 #3: 
ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xd0/0x760 net/core/dev.c:13317
 #4: ffff88813ff77348 (&root->kernfs_supers_rwsem
){++++}-{4:4}
, at: kernfs_remove_by_name_ns+0x3f/0x140 fs/kernfs/dir.c:1791
 #5: ffff88813ff77238 (&root->kernfs_rwsem){++++}-{4:4}
, at: kernfs_remove_by_name_ns+0x4e/0x140 fs/kernfs/dir.c:1792
 #6: ffff88813ff772c0 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: rt_mutex_slowtrylock kernel/locking/rtmutex.c:1404 [inline]
 #6: ffff88813ff772c0 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: rt_mutex_try_acquire kernel/locking/rtmutex.c:325 [inline]
 #6: ffff88813ff772c0 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: __rt_mutex_lock kernel/locking/rtmutex.c:1839 [inline]
 #6: ffff88813ff772c0 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: rwbase_write_lock+0xb6/0x720 kernel/locking/rwbase_rt.c:251
locks held by kworker/u8:9/1126: 3, on CPU#1:
 #0: ffff88813ff64138 ((wq_completion)events_unbound){+.+.}-{0:0}
, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
, at: process_one_work kernel/workqueue.c:3361 [inline]
, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90006307c40 ((linkwatch_work).work){+.+.}-{0:0}
, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
, at: process_one_work kernel/workqueue.c:3361 [inline]
, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313
locks held by kworker/u8:13/1375: 3, on CPU#1:
 #0: ffff888032be3938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff888032be3938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff888032be3938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff888032be3938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90006bc7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90006bc7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90006bc7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90006bc7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffffffff8f5d5978 (rtnl_mutex
){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
){+.+.}-{4:4}, at: addrconf_dad_work+0x123/0x16e0 net/ipv6/addrconf.c:4230
locks held by dhcpcd/5255: 2, on CPU#1:
 #0: ffff88804d2b8928
 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0 net/netlink/af_netlink.c:2429
 #1: ffffffff8f5d5978 (rtnl_mutex
){+.+.}-{4:4}
, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
, at: rtnl_dump_ifinfo+0xa74/0x14b0 net/core/rtnetlink.c:2618
locks held by getty/5346: 2, on CPU#0:
 #0: ffff88803675e0a0 (&tty->ldisc_sem){++++}-{0:0}
, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900044c32e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/6101: 2, last CPU#0:
 #0: ffff8880648820e0 (&type->s_umount_key#82){+.+.}-{4:4}
, at: __super_lock fs/super.c:60 [inline]
, at: __super_lock_excl fs/super.c:75 [inline]
, at: deactivate_super+0xac/0xe0 fs/super.c:613
 #1: ffff88806329c350 (&sbi->cp_global_sem_key
){+.+.}-{4:4}
, at: f2fs_down_write fs/f2fs/f2fs.h:2469 [inline]
, at: f2fs_down_write_trace+0x34/0x1f0 fs/f2fs/checkpoint.c:181
locks held by syz.6.229/8826: 1, on CPU#0:
 #0: ffff8880648820e0 (&type->s_umount_key#82){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
 #0: ffff8880648820e0 (&type->s_umount_key#82){+.+.}-{4:4}, at: super_lock+0x289/0x3d0 fs/super.c:124
locks held by syz-executor/9354: 1, on CPU#1:
 #0: ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
 #0: ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x470/0x19f0 net/ipv4/devinet.c:978
locks held by syz-executor/9437: 7, on CPU#0:
 #0: ffff888036950510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
 #0: ffff888036950510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88805f69a478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff8880297a0c38 (kn->active#51){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff8880297a0c38 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee45df8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
 #4: ffff88806dcd4160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #4: ffff88806dcd4160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
 #4: ffff88806dcd4160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369
 #5: ffff88803f0c0310 (&devlink->lock_key#34){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1724
 #6: ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
 #6: ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2188
locks held by syz-executor/9456: 4, on CPU#1:
 #0: ffff888036950510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
 #0: ffff888036950510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
 #1: ffff88803b242478 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
 #2: ffff8880297a0c38 (kn->active#51){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
 #2: ffff8880297a0c38 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
 #3: ffffffff8ee45df8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
locks held by syz-executor/9737: 2, on CPU#0:
 #0: ffffffff8f5c7140 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x524/0x780 net/core/net_namespace.c:578
 #1: ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2d5/0x820 net/ipv4/ip_tunnel.c:1136
locks held by syz-executor/9760: 2, on CPU#0:
 #0: ffffffff8f5c7140 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x524/0x780 net/core/net_namespace.c:578
 #1: ffffffff8f5d5978 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2d5/0x820 net/ipv4/ip_tunnel.c:1136

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 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/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: 4948 Comm: klogd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:unix_may_send net/unix/af_unix.c:285 [inline]
RIP: 0010:unix_dgram_sendmsg+0x8aa/0x17b0 net/unix/af_unix.c:2194
Code: 00 00 48 89 44 24 20 48 89 7c 24 70 48 89 9c 24 90 00 00 00 e8 37 b6 5e 01 31 ff 48 8b 74 24 58 e8 cb 23 ca f7 42 80 3c 3b 00 <48> 8b 5c 24 10 4c 8b 64 24 18 74 08 4c 89 e7 e8 b2 15 36 f8 49 8b
RSP: 0018:ffffc900042cfac0 EFLAGS: 00000246
RAX: ffffffff89fcba35 RBX: 1ffff11006d2fc13 RCX: ffff888036eebe80
RDX: 0000000000000000 RSI: 7fffffffffffffff RDI: 0000000000000000
RBP: ffffc900042cfc78 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f64590 R12: ffff88803697d800
R13: 1ffff92000859f74 R14: ffffc900042cfbc0 R15: dffffc0000000000
FS:  00007f44381b8c80(0000) GS:ffff888125cc2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562d65d6c450 CR3: 0000000037148000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 __sys_sendto+0x41e/0x5d0 net/socket.c:2281
 __do_sys_sendto net/socket.c:2288 [inline]
 __se_sys_sendto net/socket.c:2284 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2284
 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: 0033:0x7f4438308407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff97554a50 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f44381b8c80 RCX: 00007f4438308407
RDX: 0000000000000052 RSI: 00007fff97554b90 RDI: 0000000000000003
RBP: 00007fff97554fc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fff97554fd8
R13: 00007fff97554b90 R14: 0000000000000037 R15: 00007fff97554b90
 </TASK>