INFO: task syz-executor:4267 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22640 pid:4267 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 wb_wait_for_completion+0x16f/0x290 fs/fs-writeback.c:191 __writeback_inodes_sb_nr+0x226/0x280 fs/fs-writeback.c:2670 sync_filesystem+0x9f/0x220 fs/sync.c:54 generic_shutdown_super+0x6b/0x340 fs/super.c:474 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x42c/0x4b0 fs/namespace.c:1191 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f163379e017 RSP: 002b:00007fffddd32d98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f1633832120 RCX: 00007f163379e017 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffddd32e50 RBP: 00007fffddd32e50 R08: 00007fffddd33e50 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffddd33ee0 R13: 00007f1633832120 R14: 000000000006d150 R15: 00007fffddd33f20 Showing all locks held in the system: 2 locks held by kworker/u4:0/9: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2df70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2e790 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/27: #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 3 locks held by kworker/0:2/125: #0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:546 #1: ffff8880b8e27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x312/0x6d0 kernel/sched/psi.c:987 #2: ffff8880b8e28458 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999 2 locks held by getty/4027: #0: ffff88803015e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198 1 lock held by syz-executor/4267: #0: ffff88802ee5e0e0 (&type->s_umount_key#31){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362 2 locks held by kworker/1:5/4315: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc900046bfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 2 locks held by kworker/u4:20/4676: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc90006087d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 2 locks held by syz.5.1258/9324: #0: ffff8880799d34b8 (&nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_valid_genid+0x37/0x100 net/netfilter/nf_tables_api.c:10232 #1: ffffffff8cb332b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #1: ffffffff8cb332b8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962 2 locks held by syz.5.1258/9328: 1 lock held by modprobe/9342: #0: ffff8880b8e3ab18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xa5/0x140 kernel/sched/core.c:546 1 lock held by modprobe/9348: 2 locks held by dhcpcd-run-hook/9350: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 125 Comm: kworker/0:2 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events nsim_fib_event_work RIP: 0010:lockdep_hardirqs_on_prepare+0xd4/0x770 kernel/locking/lockdep.c:4296 Code: c2 6e 9e 7e 85 c0 0f 85 74 03 00 00 48 c7 c0 40 01 c0 96 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 18 05 00 00 83 3d 6c f9 5b 15 00 <75> 79 c6 44 13 04 00 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 f7 RSP: 0018:ffffc90002db74e0 EFLAGS: 00000046 RAX: 0000000000000004 RBX: 1ffff920005b6ea0 RCX: ffffffff96c00103 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff8a380e82 RBP: ffffc90002db7588 R08: ffff8880176263c3 R09: 1ffff11002ec4c78 R10: dffffc0000000000 R11: ffffed1002ec4c79 R12: dffffc0000000000 R13: ffffffff7fffffff R14: ffff8880176263c0 R15: 1ffff920005b6eb4 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb864a217e8 CR3: 000000000c88e000 CR4: 00000000003506f0 Call Trace: trace_hardirqs_on+0x34/0x40 kernel/trace/trace_preemptirq.c:49 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x82/0x120 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __unfreeze_partials+0x161/0x200 mm/slub.c:2584 put_cpu_partial+0x17c/0x250 mm/slub.c:2667 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] __kmem_cache_alloc_node+0x140/0x260 mm/slub.c:3398 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] nsim_fib4_rt_create drivers/net/netdevsim/fib.c:280 [inline] nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:426 [inline] nsim_fib4_event drivers/net/netdevsim/fib.c:464 [inline] nsim_fib_event drivers/net/netdevsim/fib.c:884 [inline] nsim_fib_event_work+0x891/0x3450 drivers/net/netdevsim/fib.c:1494 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292 process_scheduled_works kernel/workqueue.c:2355 [inline] worker_thread+0xd27/0x1270 kernel/workqueue.c:2441 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295