INFO: task kworker/u8:10:20356 blocked for more than 143 seconds. Not tainted 6.15.0-syzkaller-12058-g64980441d269 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:10 state:D stack:21160 pid:20356 tgid:20356 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 afs_cell_purge+0x3d9/0x540 fs/afs/cell.c:893 afs_net_exit+0x50/0x100 fs/afs/main.c:147 ops_exit_list net/core/net_namespace.c:200 [inline] ops_undo_list+0x49a/0x990 net/core/net_namespace.c:253 cleanup_net+0x4c5/0x800 net/core/net_namespace.c:686 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 3 locks held by ksoftirqd/0/15: #0: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:614 #1: ffffe8ffffc6c808 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x16a/0x6d0 kernel/sched/psi.c:937 #2: ffffffff8e8ce0d8 (pool_lock#2){-.-.}-{2:2}, at: class_raw_spinlock_constructor include/linux/spinlock.h:535 [inline] #2: ffffffff8e8ce0d8 (pool_lock#2){-.-.}-{2:2}, at: pcpu_free lib/debugobjects.c:311 [inline] #2: ffffffff8e8ce0d8 (pool_lock#2){-.-.}-{2:2}, at: __free_object+0x260/0x6c0 lib/debugobjects.c:521 1 lock held by khungtaskd/31: #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13f060 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 1 lock held by udevd/5205: 2 locks held by getty/5593: #0: ffff8880351020a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 3 locks held by syz-executor/15701: #0: ffff8880b863b918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:614 #1: ffff8880b8723f08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39a/0x6d0 kernel/sched/psi.c:987 #2: ffff8880581bc958 (&sb->s_type->i_lock_key#9){+.+.}-{3:3}, at: spin_trylock include/linux/spinlock.h:361 [inline] #2: ffff8880581bc958 (&sb->s_type->i_lock_key#9){+.+.}-{3:3}, at: lock_for_kill+0x84/0x210 fs/dcache.c:714 3 locks held by kworker/u8:2/19949: 3 locks held by kworker/u8:10/20356: #0: ffff88801b2fe148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801b2fe148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000dde7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000dde7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 #2: ffffffff8f5029d0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:662 1 lock held by syz.3.5190/22966: #0: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: netdev_wait_allrefs_any net/core/dev.c:11280 [inline] #0: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: netdev_run_todo+0x79b/0xea0 net/core/dev.c:11392 2 locks held by syz.1.5384/23654: #0: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink+0x331/0x710 net/core/rtnetlink.c:3545 #1: ffffffff8e144b78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #1: ffffffff8e144b78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:998 2 locks held by syz.1.5384/23663: #0: ffffffff8f575730 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x930 net/wireless/nl80211.c:16733 2 locks held by syz.5.5383/23656: #0: ffff888059ea86d0 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2388 #1: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f50f5c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6812 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-syzkaller-12058-g64980441d269 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:470 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 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: 5893 Comm: kworker/0:6 Not tainted 6.15.0-syzkaller-12058-g64980441d269 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_long defense_work_handler RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline] RIP: 0010:lock_release+0x63/0x3e0 kernel/locking/lockdep.c:5884 Code: 00 89 c0 48 0f a3 05 0c bb 02 0e 73 16 e8 55 e0 08 00 84 c0 75 0d f6 05 d6 a6 ec 0d 01 0f 84 ad 02 00 00 83 3d 2d ec 02 0e 00 <0f> 84 44 02 00 00 65 8b 05 30 aa fe 10 85 c0 0f 85 35 02 00 00 65 RSP: 0018:ffffc90000007750 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffc90000007801 RCX: a967350a54fee300 RDX: ffffffff903d6901 RSI: ffffffff8be28320 RDI: ffffffff8be282e0 RBP: dffffc0000000000 R08: ffffc900000078e7 R09: 0000000000000000 R10: ffffc900000078d8 R11: fffff52000000f1d R12: ffffc90000007c30 R13: ffffffff81729de5 R14: ffffffff8e13f060 R15: ffffffff81729de5 FS: 0000000000000000(0000) GS:ffff888125c55000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000033002ffc CR3: 00000000771e0000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4745 rcu_do_batch kernel/rcu/tree.c:2576 [inline] rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2832 handle_softirqs+0x286/0x870 kernel/softirq.c:579 do_softirq+0xec/0x180 kernel/softirq.c:480 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407 local_bh_enable include/linux/bottom_half.h:33 [inline] update_defense_level+0x8d2/0xd80 net/netfilter/ipvs/ip_vs_ctl.c:210 defense_work_handler+0x2d/0xd0 net/netfilter/ipvs/ip_vs_ctl.c:235 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 vkms_vblank_simulate: vblank timer overrun