INFO: task syz.4.4566:15431 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.4566 state:D stack:28160 pid:15431 tgid:15426 ppid:5852 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0x164/0x360 kernel/sched/core.c:7005 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7062 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 device_lock include/linux/device.h:895 [inline] usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 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: 0033:0x7fccd5d5cfce RSP: 002b:00007fccd3ff5b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fccd3ff66c0 RCX: 00007fccd5d5cfce RDX: 000000000002a401 RSI: 00007fccd3ff5c00 RDI: ffffffffffffff9c RBP: 00007fccd3ff5c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fccd6016038 R14: 00007fccd6015fa0 R15: 00007fccd613fa48 Showing all locks held in the system: 6 locks held by kworker/0:0/9: #0: ffff8880212df948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff8880212df948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc900000e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc900000e7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffff88802a014198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #2: ffff88802a014198 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899 #3: ffff88802a059518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88802a059518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff88802a059518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff88802a059518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff88802a059518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x217a/0x4f30 drivers/usb/core/hub.c:5953 #4: ffff888028e4f268 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff888028e4f268 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff888028e4f268 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff888028e4f268 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21a2/0x4f30 drivers/usb/core/hub.c:5953 #5: ffffffff8f473ab0 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x14e/0x1840 drivers/usb/core/hub.c:3067 1 lock held by khungtaskd/31: #0: ffffffff8e75e3e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75e3e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75e3e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5588: #0: ffff8880365b80a0 (&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+0x45c/0x13c0 drivers/tty/n_tty.c:2211 6 locks held by kworker/0:3/5833: 1 lock held by syz.4.4566/15431: #0: ffff8880299ed198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #0: ffff8880299ed198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x182/0x770 drivers/usb/core/devio.c:1054 4 locks held by kworker/1:7/15838: #0: ffff88813fe0f148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff88813fe0f148 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc9000fccfc40 ((work_completion)(&helper->damage_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc9000fccfc40 ((work_completion)(&helper->damage_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffff888025c81a80 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:235 [inline] #2: ffff888025c81a80 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_damage_work+0x125/0x750 drivers/gpu/drm/drm_fb_helper.c:274 #3: ffff888025caa130 (&dev->master_mutex){+.+.}-{4:4}, at: drm_master_internal_acquire+0x20/0x80 drivers/gpu/drm/drm_auth.c:435 3 locks held by syz.5.6857/29648: 2 locks held by syz.0.6859/29652: 2 locks held by syz.1.6860/29655: 5 locks held by syz.3.6861/29657: ============================================= 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 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: 29652 Comm: syz.0.6859 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d 24 42 55 0c 48 89 de 5b e9 73 96 5e 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0d 48 32 56 11 65 8b 15 69 32 56 RSP: 0018:ffffc9001fdaf580 EFLAGS: 00000283 RAX: ffffffff82196549 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: ffff8880304e9e80 RSI: 00000000000001fd RDI: 000000000000010d RBP: 000000000000010d R08: ffffea000048bab3 R09: 1ffffd4000091756 R10: dffffc0000000000 R11: fffff94000091757 R12: ffff88803a27a000 R13: 00000000000001fd R14: 1ffff92003fb5f5d R15: ffffc9001fdafac0 FS: 0000000000000000(0000) GS:ffff888125563000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000002000 CR3: 000000005de3a000 CR4: 00000000003526f0 Call Trace: __tlb_remove_folio_pages_size+0x153/0x5a0 mm/mmu_gather.c:197 zap_present_folio_ptes mm/memory.c:1672 [inline] zap_present_ptes mm/memory.c:1725 [inline] do_zap_pte_range mm/memory.c:1827 [inline] zap_pte_range mm/memory.c:1929 [inline] zap_pmd_range mm/memory.c:2021 [inline] zap_pud_range mm/memory.c:2049 [inline] zap_p4d_range mm/memory.c:2070 [inline] unmap_page_range+0x1d3c/0x48f0 mm/memory.c:2091 unmap_single_vma mm/memory.c:2133 [inline] unmap_vmas+0x48f/0x6a0 mm/memory.c:2171 exit_mmap+0x280/0xa10 mm/mmap.c:1302 __mmput+0x118/0x430 kernel/fork.c:1174 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x6a2/0x23c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 __do_sys_exit_group kernel/exit.c:1129 [inline] __se_sys_exit_group kernel/exit.c:1127 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1127 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7fe71419c799 Code: Unable to access opcode bytes at 0x7fe71419c76f. RSP: 002b:00007fe71453fd88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe71419c799 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fe71453fdec R08: 0000000000000006 R09: 00000000000927c0 R10: 00000000005faffc R11: 0000000000000246 R12: 0000000000000522 R13: 00000000000927c0 R14: 0000000000091140 R15: 00007fe71453fe40