INFO: task syz.5.1009:14895 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.1009 state:D stack:29024 pid:14895 tgid:14859 ppid:14390 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_rmdir+0x1cd/0x520 fs/namei.c:5386 __do_sys_rmdir fs/namei.c:5416 [inline] __se_sys_rmdir+0x2e/0x140 fs/namei.c:5413 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: 0033:0x7f7b4eb1c799 RSP: 002b:00007f7b4cd34028 EFLAGS: 00000246 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 00007f7b4ed96180 RCX: 00007f7b4eb1c799 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000400 RBP: 00007f7b4ebb2c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7b4ed96218 R14: 00007f7b4ed96180 R15: 00007ffd2571dd58 Showing all locks held in the system: 1 lock held by khungtaskd/37: #0: ffffffff8ddcb840 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcb840 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcb840 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:5/88: #0: ffff88801aee5938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff88801aee5938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc9000156fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc9000156fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffff88803d29a0d0 (&type->s_umount_key#62){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff88806830a8e8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 3 locks held by kworker/u8:7/173: #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc90003b07c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc90003b07c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 3 locks held by kworker/1:2/809: #0: ffff888019c03938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff888019c03938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc90004ab7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc90004ab7c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffff88802b13d260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490 6 locks held by kworker/u8:8/1161: #0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc9000585fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc9000585fc40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffffffff8f14b840 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675 #3: ffff8880366ae0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #3: ffff8880366ae0d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff8880366ae0d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x117/0x3f0 net/devlink/core.c:504 #4: ffff888038c80300 (&devlink->lock_key#37){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:274 [inline] #4: ffff888038c80300 (&devlink->lock_key#37){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff888038c80300 (&devlink->lock_key#37){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x3f0 net/devlink/core.c:504 #5: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #5: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: register_netdevice_notifier_net+0x1a/0xa0 net/core/dev.c:2102 3 locks held by kworker/u8:9/3498: 2 locks held by dhcpcd/5456: #0: ffffffff8f1c85a0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x930 net/wireless/nl80211.c:18061 2 locks held by getty/5551: #0: ffff8880375cd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 3 locks held by kworker/1:10/14715: #0: ffff888019c03938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff888019c03938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc90004c97c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc90004c97c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffff888064d80260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x222/0x3e0 drivers/net/netdevsim/fib.c:1490 4 locks held by syz.5.1009/14860: 2 locks held by syz.5.1009/14895: #0: ffff88803d29a480 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff88806830acb8 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff88806830acb8 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff88806830acb8 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff88806830acb8 (&type->i_mutex_dir_key#11/1){+.+.}-{4:4}, at: filename_rmdir+0x1cd/0x520 fs/namei.c:5386 3 locks held by kworker/u8:2/15871: #0: ffff888032224138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff888032224138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc9000e7afc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc9000e7afc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4198 1 lock held by syz-executor/16565: #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x65f/0xe30 net/ipv6/addrconf.c:5031 1 lock held by syz-executor/16607: #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071 7 locks held by syz-executor/16691: #0: ffff888037b9a480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff888037b9a480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684 #1: ffff88802437c078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #2: ffff888028eaff08 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888028eaff08 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 #3: ffffffff8e9c78b8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 #4: ffff8880339650d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #4: ffff8880339650d8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1106 [inline] #4: ffff8880339650d8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x870 drivers/base/dd.c:1304 #5: ffff88803b780300 (&devlink->lock_key#33){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1778 #6: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0xed/0x680 drivers/net/netdevsim/netdev.c:1177 1 lock held by syz-executor/16739: #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f159ff8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071 4 locks held by syz-executor/16743: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 37 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: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: 3498 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: kvfree_rcu_reclaim kfree_rcu_monitor RIP: 0010:check_preemption_disabled+0x22/0xe0 lib/smp_processor_id.c:53 Code: 90 90 90 90 90 90 90 90 55 41 57 41 56 53 65 8b 05 47 93 2b 07 65 8b 0d 3c 93 2b 07 f7 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f 5d 99 a5 03 00 cc 9c 59 f7 c1 00 02 00 00 74 ea 65 4c 8b 3d ee 92 RSP: 0018:ffffc9000ebcf358 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff821f1313 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8ba65de0 RDI: ffffffff8ba65da0 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc9000ebcf518 R11: ffffffff81af65f0 R12: 0000000000000002 R13: ffffffff8ddcb840 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812643f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff67cfb35c0 CR3: 0000000077e24000 CR4: 00000000003526f0 Call Trace: rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:752 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x57/0x2e0 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 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:2692 [inline] slab_free_freelist_hook mm/slub.c:2721 [inline] slab_free_bulk mm/slub.c:6205 [inline] kmem_cache_free_bulk+0x313/0x1220 mm/slub.c:7009 kfree_bulk include/linux/slab.h:823 [inline] kvfree_rcu_bulk+0xe5/0x1b0 mm/slab_common.c:1502 kvfree_rcu_drain_ready mm/slab_common.c:1704 [inline] kfree_rcu_monitor+0x211/0x2a0 mm/slab_common.c:1777 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: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