INFO: task syz.3.2206:16922 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.2206 state:D stack:25088 pid:16922 tgid:16921 ppid:11019 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 request_wait_answer fs/fuse/dev.c:567 [inline] __fuse_request_send fs/fuse/dev.c:581 [inline] __fuse_simple_request+0xf15/0x18d0 fs/fuse/dev.c:675 fuse_simple_request fs/fuse/fuse_i.h:1250 [inline] fuse_access fs/fuse/dir.c:1530 [inline] fuse_permission+0x855/0xdc0 fs/fuse/dir.c:1609 do_inode_permission fs/namei.c:526 [inline] inode_permission+0x285/0x470 fs/namei.c:593 path_permission include/linux/fs.h:3086 [inline] __do_sys_chdir fs/open.c:565 [inline] __se_sys_chdir+0x107/0x280 fs/open.c:555 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff40af8eba9 RSP: 002b:00007ff40bea9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000050 RAX: ffffffffffffffda RBX: 00007ff40b1d5fa0 RCX: 00007ff40af8eba9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000040 RBP: 00007ff40b011e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff40b1d6038 R14: 00007ff40b1d5fa0 R15: 00007ffe70b17918 INFO: task syz.3.2206:16925 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.2206 state:D stack:26920 pid:16925 tgid:16921 ppid:11019 task_flags:0x400740 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common+0x3da/0x710 kernel/sched/completion.c:121 wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion_state+0x1c/0x40 kernel/sched/completion.c:269 coredump_wait fs/coredump.c:534 [inline] vfs_coredump+0x8cf/0x2a60 fs/coredump.c:1131 get_signal+0x1109/0x1340 kernel/signal.c:3019 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff40af8eba9 RSP: 002b:00007ff40be670e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 00000000000000ca RBX: 00007ff40b1d6188 RCX: 00007ff40af8eba9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007ff40b1d618c RBP: 00007ff40b1d6180 R08: 7fffffffffffffff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff40b1d6218 R14: 00007ffe70b17830 R15: 00007ffe70b17918 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 6 locks held by kworker/u8:3/44: #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90000b47ba0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90000b47ba0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffff88801a8a10b8 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x38/0x6e0 drivers/tty/tty_buffer.c:467 #3: ffff8880568d00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263 #4: ffff8880568d02e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_receive_buf_common+0x84/0x12f0 drivers/tty/n_tty.c:1686 #5: ffffc900033bd380 (&ldata->output_lock){+.+.}-{4:4}, at: commit_echoes drivers/tty/n_tty.c:740 [inline] #5: ffffc900033bd380 (&ldata->output_lock){+.+.}-{4:4}, at: n_tty_receive_char+0x683/0xc30 drivers/tty/n_tty.c:1421 2 locks held by kworker/u8:4/61: 2 locks held by kworker/u8:5/2209: #0: ffff888022af1148 ((wq_completion)quota_events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff888022af1148 ((wq_completion)quota_events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90005667ba0 ((quota_release_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90005667ba0 ((quota_release_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 3 locks held by kworker/u8:7/3001: #0: ffff88814ccac148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88814ccac148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000c1d7ba0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000c1d7ba0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194 2 locks held by dhcpcd/5525: #0: ffffffff8f724f48 (vlan_ioctl_mutex){+.+.}-{4:4}, at: sock_ioctl+0x5ee/0x790 net/socket.c:1324 #1: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: vlan_ioctl_handler+0xd0/0x650 net/8021q/vlan.c:577 2 locks held by getty/5614: #0: ffff8880303af0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by kworker/u8:9/6249: #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90003467ba0 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90003467ba0 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 5 locks held by kworker/0:7/7940: #0: ffff888143ad6548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff888143ad6548 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90003557ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90003557ba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffff8880284d0198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #2: ffff8880284d0198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898 #3: ffff88807b02f198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #3: ffff88807b02f198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006 #4: ffff888071200160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #4: ffff888071200160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x400 drivers/base/dd.c:1006 1 lock held by udevd/10814: 3 locks held by kworker/u8:14/13046: 2 locks held by kworker/u8:19/13053: #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801a889148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000437fba0 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000437fba0 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 3 locks held by kworker/0:4/16236: #0: ffff88801e288148 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88801e288148 ((wq_completion)pm){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000bed7ba0 ((work_completion)(&hcd->wakeup_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000bed7ba0 ((work_completion)(&hcd->wakeup_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffff88814576b198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline] #2: ffff88814576b198 (&dev->mutex){....}-{4:4}, at: usb_remote_wakeup+0x23/0x100 drivers/usb/core/hub.c:3885 5 locks held by kworker/u8:27/18794: 1 lock held by syz-executor/18941: #0: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f740a48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056 3 locks held by syz.7.2562/19107: 2 locks held by syz.2.2569/19116: 1 lock held by syz.8.2571/19134: 10 locks held by syz.0.2573/19140: #0: ffff8880568d00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffff8880568d0130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: tty_write_lock drivers/tty/tty_io.c:939 [inline] #1: ffff8880568d0130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: iterate_tty_write drivers/tty/tty_io.c:958 [inline] #1: ffff8880568d0130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write+0x211/0xa30 drivers/tty/tty_io.c:1081 #2: ffff8880568d02e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_write+0x1e0/0x1200 drivers/tty/n_tty.c:2360 #3: ffffc900033bd380 (&ldata->output_lock){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:228 [inline] #3: ffffc900033bd380 (&ldata->output_lock){+.+.}-{4:4}, at: process_output_block drivers/tty/n_tty.c:517 [inline] #3: ffffc900033bd380 (&ldata->output_lock){+.+.}-{4:4}, at: n_tty_write+0x653/0x1200 drivers/tty/n_tty.c:2377 #4: ffffffff8e330860 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:669 [inline] #4: ffffffff8e330860 (console_lock){+.+.}-{0:0}, at: do_con_write+0x116/0x5210 drivers/tty/vt/vt.c:3193 #5: ffff888142b7a280 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_pan_display+0xbe/0xbd0 drivers/gpu/drm/drm_fb_helper.c:1441 #6: ffff888142b9e128 (&dev->master_mutex){+.+.}-{4:4}, at: drm_master_internal_acquire+0x20/0x80 drivers/gpu/drm/drm_auth.c:435 #7: ffff888142b7a098 (&client->modeset_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_locked+0x4c/0x4d0 drivers/gpu/drm/drm_client_modeset.c:1204 #8: ffffc9000f0a7190 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_client_modeset_commit_atomic+0xda/0x760 drivers/gpu/drm/drm_client_modeset.c:1042 #9: ffffc9000f0a71b8 (crtc_ww_class_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_atomic+0xda/0x760 drivers/gpu/drm/drm_client_modeset.c:1042 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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: 18794 Comm: kworker/u8:27 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: netns cleanup_net RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:100 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x12d6/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: 8b 7c 24 18 e8 4b 6e b0 00 48 8b 44 24 18 48 8b 10 48 c7 c7 00 5e a8 8b 89 de e8 15 d5 b3 ff e9 43 06 00 00 49 89 d5 48 89 d5 <48> 89 d8 48 29 e8 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83 RSP: 0018:ffffc9000bb56d38 EFLAGS: 00000287 RAX: ffffffff90326140 RBX: ffffffff90326140 RCX: ffffffff90326148 RDX: ffffffff9032613c RSI: ffffffff90dbcd82 RDI: ffffffff8c036ea0 RBP: ffffffff9032613c R08: 0000000000000005 R09: ffffffff8173bd25 R10: ffffc9000bb56e58 R11: ffffffff81ac3160 R12: ffffffff896d2d78 R13: ffffffff9032613c R14: ffffc9000bb56e08 R15: ffffffff90326144 FS: 0000000000000000(0000) GS:ffff888125ae8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555f7b5808 CR3: 000000008ceee000 CR4: 00000000003526f0 Call Trace: 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:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5457 kmalloc_noprof include/linux/slab.h:956 [inline] addr_event+0xc3/0x470 drivers/infiniband/core/roce_gid_mgmt.c:861 inet6addr_event+0x9f/0xd0 drivers/infiniband/core/roce_gid_mgmt.c:904 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85 atomic_notifier_call_chain+0xda/0x180 kernel/notifier.c:223 addrconf_ifdown+0xe76/0x1880 net/ipv6/addrconf.c:3978 addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] netif_close_many+0x29c/0x410 net/core/dev.c:1784 unregister_netdevice_many_notify+0x7b9/0x1ff0 net/core/dev.c:12185 unregister_netdevice_many net/core/dev.c:12278 [inline] default_device_exit_batch+0x819/0x890 net/core/dev.c:12782 ops_exit_list net/core/net_namespace.c:204 [inline] ops_undo_list+0x525/0x990 net/core/net_namespace.c:251 cleanup_net+0x4c5/0x800 net/core/net_namespace.c:682 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245