INFO: task syz.3.217:7391 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.217 state:D stack:28472 pid:7391 tgid:7388 ppid:5796 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x145f/0x5070 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:1027 [inline] open_last_lookups fs/namei.c:4546 [inline] path_openat+0xb53/0x3df0 fs/namei.c:4793 do_filp_open+0x1fa/0x410 fs/namei.c:4823 do_sys_openat2+0x121/0x200 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_creat fs/open.c:1514 [inline] __se_sys_creat fs/open.c:1508 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1508 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbc9e74f749 RSP: 002b:00007fbc9456c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007fbc9e9a6180 RCX: 00007fbc9e74f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000e00 RBP: 00007fbc9e7d3f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbc9e9a6218 R14: 00007fbc9e9a6180 R15: 00007ffe76f63f88 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:10/1434: #0: ffff88801d689938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801d689938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc90005197bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90005197bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffff888060d440d0 (&type->s_umount_key#67){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff88805ed5cfe8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 2 locks held by getty/5555: #0: ffff88814e0e00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x44f/0x1460 drivers/tty/n_tty.c:2211 2 locks held by syz-executor/5797: 1 lock held by udevd/5972: 3 locks held by kworker/u8:17/6079: #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc90006097bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90006097bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8e898840 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7b0 net/core/net_namespace.c:670 4 locks held by syz.3.217/7390: 2 locks held by syz.3.217/7391: #0: ffff888060d44480 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88805ed5d3b8 (&type->i_mutex_dir_key#12){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88805ed5d3b8 (&type->i_mutex_dir_key#12){++++}-{4:4}, at: open_last_lookups fs/namei.c:4546 [inline] #1: ffff88805ed5d3b8 (&type->i_mutex_dir_key#12){++++}-{4:4}, at: path_openat+0xb53/0x3df0 fs/namei.c:4793 5 locks held by syz-executor/7468: 7 locks held by syz-executor/8860: 2 locks held by syz-executor/8883: #0: ffffffff8e898840 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cc/0x570 net/core/net_namespace.c:577 #1: ffffffff8e8a5978 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline] #1: ffffffff8e8a5978 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11506 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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:160 [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:346 [inline] watchdog+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8860 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:rt_mutex_owner include/linux/rtmutex.h:52 [inline] RIP: 0010:rt_mutex_slowtrylock kernel/locking/rtmutex.c:1384 [inline] RIP: 0010:rt_mutex_try_acquire kernel/locking/rtmutex.c:320 [inline] RIP: 0010:__rt_mutex_lock kernel/locking/rtmutex.c:1812 [inline] RIP: 0010:rwbase_write_lock+0x8f/0x750 kernel/locking/rwbase_rt.c:244 Code: 89 f7 e8 74 71 4e f7 49 83 3e 00 0f 85 a1 05 00 00 4d 8d 77 58 4c 89 f3 48 c1 eb 03 48 b8 00 00 00 00 00 fc ff df 80 3c 03 00 <74> 08 4c 89 f7 e8 47 71 4e f7 4d 8d 6f 08 49 8b 06 48 83 f8 01 4c RSP: 0018:ffffc90011edeb18 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 1ffff11027fee846 RCX: dffffc0000000000 RDX: 0000000047bdea00 RSI: 0000000000000002 RDI: ffff88813ff741d8 RBP: 0000000000000002 R08: ffffffff82590231 R09: ffff88813ff74238 R10: dffffc0000000000 R11: ffffed100739eb87 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff88813ff74230 R15: ffff88813ff741d8 FS: 0000555564c5d500(0000) GS:ffff888126cee000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3a31534000 CR3: 000000002135c000 CR4: 00000000003526f0 Call Trace: kernfs_add_one+0x41/0x5c0 fs/kernfs/dir.c:796 __kernfs_create_file+0x22b/0x2e0 fs/kernfs/file.c:1086 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x667/0x1170 fs/sysfs/group.c:189 internal_create_groups fs/sysfs/group.c:229 [inline] sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255 device_add_groups drivers/base/core.c:2836 [inline] device_add_attrs+0xe0/0x5a0 drivers/base/core.c:2900 device_add+0x496/0xb80 drivers/base/core.c:3643 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2358 register_netdevice+0x125b/0x1a80 net/core/dev.c:11393 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3840 __rtnl_newlink net/core/rtnetlink.c:3957 [inline] rtnl_newlink+0x16e7/0x1c90 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x846/0xa10 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3c7/0x520 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ffadff715dc 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:00007ffcec34b980 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ffae0cf4620 RCX: 00007ffadff715dc RDX: 000000000000003c RSI: 00007ffae0cf4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffcec34b9d4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007ffae0cf4670 R15: 0000000000000000