INFO: task syz-executor:5774 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:21576 pid:5774 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 wb_wait_for_completion+0x173/0x2a0 fs/fs-writeback.c:192 sync_inodes_sb+0x1c9/0xa10 fs/fs-writeback.c:2778 sync_filesystem+0x171/0x220 fs/sync.c:64 generic_shutdown_super+0x6f/0x2b0 fs/super.c:666 kill_block_super+0x44/0x90 fs/super.c:1660 deactivate_locked_super+0x97/0x100 fs/super.c:481 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259 task_work_run+0x1d4/0x260 kernel/task_work.c:245 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x95a/0x2460 kernel/exit.c:883 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024 __do_sys_exit_group kernel/exit.c:1035 [inline] __se_sys_exit_group kernel/exit.c:1033 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f06ae59c629 RSP: 002b:00007fff69a8ffc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f06ae631f50 RCX: 00007f06ae59c629 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 000000000000000c R08: 0000000000000000 R09: 00007f06ae631ef0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff69a91280 R13: 00007f06ae631ef0 R14: 00005555806244e8 R15: 00007fff69a92350 Showing all locks held in the system: 2 locks held by kworker/u4:0/11: 1 lock held by khungtaskd/29: #0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8d131fa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 3 locks held by kworker/0:2/788: #0: ffff888019a91d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888019a91d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffffc90003987d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90003987d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #2: ffff8881437f4190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #2: ffff8881437f4190 (&dev->mutex){....}-{3:3}, at: hub_event+0x180/0x49f0 drivers/usb/core/hub.c:5861 2 locks held by kworker/0:3/1201: #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffffc90004b1fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc90004b1fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 2 locks held by getty/5530: #0: ffff8880315720a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217 4 locks held by udevd/5761: #0: ffff88801af671c8 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb1/0xd50 fs/seq_file.c:182 #1: ffff888024483888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x5c/0x410 fs/kernfs/file.c:172 #2: ffff8880263ca008 (kn->active#23){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8880263ca008 (kn->active#23){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x410 fs/kernfs/file.c:173 #3: ffff88807e5ed190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:1000 [inline] #3: ffff88807e5ed190 (&dev->mutex){....}-{3:3}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 2 locks held by syz-executor/5774: #0: ffff88805bee40e0 (&type->s_umount_key#83){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805bee40e0 (&type->s_umount_key#83){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805bee40e0 (&type->s_umount_key#83){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513 #1: ffff8880218667d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline] #1: ffff8880218667d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1ad/0xa10 fs/fs-writeback.c:2776 8 locks held by kworker/0:4/5848: #0: ffff888019a91d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888019a91d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #1: ffffc900048bfd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc900048bfd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2711 #2: ffff8881433a4190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #2: ffff8881433a4190 (&dev->mutex){....}-{3:3}, at: hub_event+0x180/0x49f0 drivers/usb/core/hub.c:5861 #3: ffff88807e5ed190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #3: ffff88807e5ed190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x10b/0x8a0 drivers/usb/core/hub.c:2306 #4: ffff88807e3d9160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #4: ffff88807e3d9160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1095 [inline] #4: ffff88807e3d9160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb6/0x7a0 drivers/base/dd.c:1292 #5: ffff888025918d68 (&gspca_dev->usb_lock){+.+.}-{3:3}, at: gspca_disconnect+0x6e/0x2d0 drivers/media/usb/gspca/gspca.c:1630 #6: ffffffff8de81088 (input_mutex){+.+.}-{3:3}, at: __input_unregister_device+0x2ee/0x5f0 drivers/input/input.c:2293 #7: ffffffff8d137978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline] #7: ffffffff8d137978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004 2 locks held by syz.0.1037/9566: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf3d/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7199 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:__might_sleep+0x4/0xe0 kernel/sched/core.c:10127 Code: 00 00 00 00 fc ff df e9 80 fe ff ff 89 d9 80 e1 07 38 c1 0f 8c 95 fe ff ff 48 89 df e8 25 05 81 00 e9 88 fe ff ff f3 0f 1e fa <55> 41 57 41 56 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 1d RSP: 0018:ffffc9000be57cd0 EFLAGS: 00000206 RAX: 0000000000400140 RBX: ffffc9000be57d30 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000132 RDI: ffffffff8c7fdb41 RBP: 0000000000000d40 R08: ffffffff8e8adeaf R09: 1ffffffff1d15bd5 R10: dffffc0000000000 R11: fffffbfff1d15bd6 R12: 0000000000000000 R13: ffff888076e3ae10 R14: ffff8881400093c0 R15: 0000000000000001 FS: 0000555581f07500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f027ffea4b8 CR3: 0000000074fca000 CR4: 00000000003506f0 Call Trace: might_alloc include/linux/sched/mm.h:306 [inline] slab_pre_alloc_hook+0x4a/0x310 mm/slab.h:714 slab_alloc_node mm/slub.c:3477 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x5a/0x2d0 mm/slub.c:3519 kmem_cache_zalloc include/linux/slab.h:711 [inline] lsm_inode_alloc security/security.c:633 [inline] security_inode_alloc+0x34/0x110 security/security.c:1494 inode_init_always+0x8fc/0xc90 fs/inode.c:232 alloc_inode fs/inode.c:268 [inline] new_inode_pseudo+0x95/0x1d0 fs/inode.c:1049 sock_alloc net/socket.c:634 [inline] __sock_create+0x12d/0x940 net/socket.c:1534 sock_create net/socket.c:1626 [inline] __sys_socket_create net/socket.c:1663 [inline] __sys_socket+0xd7/0x1a0 net/socket.c:1714 __do_sys_socket net/socket.c:1728 [inline] __se_sys_socket net/socket.c:1726 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1726 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f027fd9dec7 Code: f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd670ae408 EFLAGS: 00000202 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f027fd9dec7 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 000000000000000a RBP: 00007ffd670aeb3c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007f027ffe6e00 R13: 00000000000927c0 R14: 0000000000048671 R15: 00007f027ffe8fc0