INFO: task syz.0.341:8310 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.341 state:D stack:29024 pid:8310 tgid:8279 ppid:6857 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1073 [inline] lock_rename fs/namei.c:3756 [inline] __start_renaming+0x148/0x410 fs/namei.c:3852 filename_renameat2+0x38c/0x9c0 fs/namei.c:6119 __do_sys_rename fs/namei.c:6188 [inline] __se_sys_rename+0x55/0x2c0 fs/namei.c:6184 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4c5c5dc799 RSP: 002b:00007f4c5a80d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007f4c5c856090 RCX: 00007f4c5c5dc799 RDX: 0000000000000000 RSI: 0000200000000640 RDI: 00002000000000c0 RBP: 00007f4c5c672bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4c5c856128 R14: 00007f4c5c856090 R15: 00007ffc9473a968 INFO: task syz.0.341:8312 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.341 state:D stack:27712 pid:8312 tgid:8279 ppid:6857 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1073 [inline] __start_dirop fs/namei.c:2923 [inline] start_dirop fs/namei.c:2934 [inline] filename_create+0x200/0x370 fs/namei.c:4922 filename_mkdirat+0xd2/0x520 fs/namei.c:5259 __do_sys_mkdirat fs/namei.c:5287 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5284 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4c5c5db607 RSP: 002b:00007f4c5a7ebe58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f4c5a7ebee0 RCX: 00007f4c5c5db607 RDX: 00000000000001ff RSI: 0000200000000200 RDI: 00000000ffffff9c RBP: 0000200000000000 R08: 0000200000000740 R09: 0000000000000000 R10: 0000200000000000 R11: 0000000000000246 R12: 0000200000000200 R13: 00007f4c5a7ebea0 R14: 0000000000000000 R15: 0000200000000580 Showing all locks held in the system: 2 locks held by kthreadd/2: #0: ffffffff8de0cab0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x2360/0x3d00 kernel/fork.c:2322 #1: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: write_lock_irq include/linux/rwlock_rt.h:115 [inline] #1: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: copy_process+0x2482/0x3d00 kernel/fork.c:2369 4 locks held by kworker/u8:1/13: #0: ffff88801eaa7938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff88801eaa7938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc90000127c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffff88803ad5e0d0 (&type->s_umount_key#100){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff88806bf64fe8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 1 lock held by khungtaskd/38: #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:2/43: 4 locks held by kworker/0:2/1233: 4 locks held by kworker/u8:15/3876: 2 locks held by getty/5554: #0: ffff888028c790a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e762e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 2 locks held by kworker/u8:17/5918: 5 locks held by syz.0.341/8280: 2 locks held by syz.0.341/8310: #0: ffff88803ad5e480 (sb_writers#34){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff88806bf653b8 (&type->i_mutex_dir_key#24/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff88806bf653b8 (&type->i_mutex_dir_key#24/1){+.+.}-{4:4}, at: lock_rename fs/namei.c:3756 [inline] #1: ffff88806bf653b8 (&type->i_mutex_dir_key#24/1){+.+.}-{4:4}, at: __start_renaming+0x148/0x410 fs/namei.c:3852 2 locks held by syz.0.341/8312: #0: ffff88803ad5e480 (sb_writers#34){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff88806bf653b8 (&type->i_mutex_dir_key#24/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff88806bf653b8 (&type->i_mutex_dir_key#24/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff88806bf653b8 (&type->i_mutex_dir_key#24/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff88806bf653b8 (&type->i_mutex_dir_key#24/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4922 2 locks held by syz.3.463/9260: #0: ffff88803ad5e0d0 (&type->s_umount_key#100){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff88803ad5e0d0 (&type->s_umount_key#100){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 #1: ffff888025d608c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:398 [inline] #1: ffff888025d608c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1c5/0xc10 fs/fs-writeback.c:2922 1 lock held by syz-executor/9528: 1 lock held by syz-executor/9777: #0: ffff88803ea220d0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88803ea220d0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88803ea220d0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 1 lock held by syz-executor/9783: #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline] #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xe1/0x740 kernel/exit.c:1672 2 locks held by udevd/10077: 3 locks held by syz.6.585/10278: 2 locks held by syz.1.541/10307: #0: ffff8880355900d0 (&type->s_umount_key#75/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345 #1: ffffffff8dc6d978 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5278 [inline] #1: ffffffff8dc6d978 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9ef/0x1e90 kernel/workqueue.c:5831 1 lock held by syz.0.586/10313: 2 locks held by syz.4.526/10316: #0: ffffffff8de0cab0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x2360/0x3d00 kernel/fork.c:2322 #1: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: write_lock_irq include/linux/rwlock_rt.h:115 [inline] #1: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: copy_process+0x2482/0x3d00 kernel/fork.c:2369 1 lock held by syz.4.526/10318: #0: ffff88805b4e9218 (&uhid->waitq){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] #0: ffff88805b4e9218 (&uhid->waitq){+.+.}-{3:3}, at: finish_wait+0xbe/0x1e0 kernel/sched/wait.c:394 6 locks held by syz.4.526/10321: 1 lock held by sed/10324: #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: write_lock_irq include/linux/rwlock_rt.h:115 [inline] #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: exit_notify kernel/exit.c:742 [inline] #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: do_exit+0x729/0x2320 kernel/exit.c:983 6 locks held by udevd/10325: 1 lock held by udevd/10326: #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:38 [inline] #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: __do_sys_prctl kernel/sys.c:2559 [inline] #0: ffffffff8da0c0a8 (tasklist_lock){++++}-{3:3}, at: __se_sys_prctl+0x10ba/0x1a60 kernel/sys.c:2533 ============================================= 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 02/12/2026 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:161 [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+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 1233 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: events_power_efficient wg_ratelimiter_gc_entries RIP: 0010:__lock_release kernel/locking/lockdep.c:5544 [inline] RIP: 0010:lock_release+0x129/0x3d0 kernel/locking/lockdep.c:5889 Code: dd 00 48 89 ef 4c 89 f6 e8 c4 b6 81 09 44 89 64 24 14 45 89 e5 85 c0 0f 84 d7 00 00 00 48 85 ed 0f 84 13 01 00 00 83 7d 24 00 <0f> 85 d6 01 00 00 8b 45 20 3d 00 00 20 00 48 8b 5c 24 08 8b 54 24 RSP: 0018:ffffc900056d7960 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 000000000000000f RCX: 0000000080000002 RDX: 0000000000000001 RSI: ffffffff8e88c398 RDI: ffff888028820c30 RBP: ffff888028820c30 R08: ffffffff8e88c3d7 R09: 1ffffffff1d1187a R10: dffffc0000000000 R11: fffffbfff1d1187b R12: 0000000000000003 R13: 0000000000000003 R14: ffffffff8e88c398 R15: ffff888028820000 FS: 0000000000000000(0000) GS:ffff888126340000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb4f5631000 CR3: 0000000052876000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_irqrestore+0x1b/0x80 kernel/locking/spinlock.c:194 raw_spin_unlock_irqrestore_wake include/linux/sched/wake_q.h:97 [inline] rtlock_slowlock kernel/locking/rtmutex.c:1896 [inline] rtlock_lock kernel/locking/spinlock_rt.c:43 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline] rt_spin_lock+0x17a/0x400 kernel/locking/spinlock_rt.c:57 spin_lock include/linux/spinlock_rt.h:45 [inline] wg_ratelimiter_gc_entries+0x5d/0x480 drivers/net/wireguard/ratelimiter.c:63 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245