INFO: task syz.5.896:12881 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.896 state:D stack:24576 pid:12881 tgid:12863 ppid:10045 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289 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:3762 [inline] __start_renaming+0x148/0x410 fs/namei.c:3858 filename_renameat2+0x38c/0x9c0 fs/namei.c:6125 __do_sys_renameat2 fs/namei.c:6179 [inline] __se_sys_renameat2+0x5a/0x2c0 fs/namei.c:6174 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: 0033:0x7fc1d39dc819 RSP: 002b:00007fc1d1c15028 EFLAGS: 00000246 ORIG_RAX: 000000000000013c RAX: ffffffffffffffda RBX: 00007fc1d3c56090 RCX: 00007fc1d39dc819 RDX: 0000000000000005 RSI: 0000200000000080 RDI: ffffffffffffff9c RBP: 00007fc1d3a72c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000980 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc1d3c56128 R14: 00007fc1d3c56090 R15: 00007fff4730ee78 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:3/57: #0: ffff88801f2d7138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff88801f2d7138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc9000123fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc9000123fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffff8880575b80d0 (&type->s_umount_key#93){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff888060b78ba8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 6 locks held by kworker/u8:4/67: 2 locks held by getty/5554: #0: ffff8880282bd0a0 (&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+0x462/0x13c0 drivers/tty/n_tty.c:2211 4 locks held by syz.5.896/12864: 2 locks held by syz.5.896/12881: #0: ffff8880575b8480 (sb_writers#32){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888060b78f78 (&type->i_mutex_dir_key#18/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888060b78f78 (&type->i_mutex_dir_key#18/1){+.+.}-{4:4}, at: lock_rename fs/namei.c:3762 [inline] #1: ffff888060b78f78 (&type->i_mutex_dir_key#18/1){+.+.}-{4:4}, at: __start_renaming+0x148/0x410 fs/namei.c:3858 ============================================= 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 03/18/2026 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:436 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 67 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:unwind_next_frame+0xeb2/0x23c0 arch/x86/kernel/unwind_orc.c:-1 Code: 4c 8b 64 24 48 74 08 48 89 df e8 29 1d b4 00 48 8b 44 24 18 48 89 03 ba 10 00 00 00 4c 89 e7 31 f6 e8 f2 1e b4 00 48 8b 14 24 ca 04 00 00 4c 89 64 24 18 4d 8d 6e 08 4c 89 e8 48 c1 e8 03 48 RSP: 0018:ffffc9000152f458 EFLAGS: 00000246 RAX: ffffc9000152f578 RBX: ffffc9000152f560 RCX: 0000000000000000 RDX: ffffffff8ff94664 RSI: 0000000000000000 RDI: ffffc9000152f588 RBP: dffffc0000000000 R08: ffffc9000152f587 R09: 0000000000000000 R10: ffffc9000152f578 R11: fffff520002a5eb1 R12: ffffc9000152f578 R13: 1ffff920002a5ea7 R14: ffffc9000152f528 R15: ffffc9000152f570 FS: 0000000000000000(0000) GS:ffff888126435000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055a20c5e6168 CR3: 000000000dbba000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1c1/0x6c0 mm/slub.c:6483 skb_kfree_head net/core/skbuff.c:1089 [inline] skb_free_head net/core/skbuff.c:1101 [inline] skb_release_data+0x6f0/0x940 net/core/skbuff.c:1128 skb_release_all net/core/skbuff.c:1203 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1217 nsim_dev_trap_report drivers/net/netdevsim/dev.c:892 [inline] nsim_dev_trap_report_work+0x7fa/0xbc0 drivers/net/netdevsim/dev.c:922 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245