INFO: task udevd:5778 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:24904 pid:5778 ppid:5138 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 io_schedule+0x80/0xd0 kernel/sched/core.c:9022 folio_wait_bit_common+0x6eb/0xf70 mm/filemap.c:1329 folio_put_wait_locked mm/filemap.c:1493 [inline] do_read_cache_folio+0x1c0/0x7e0 mm/filemap.c:3786 read_mapping_folio include/linux/pagemap.h:898 [inline] read_part_sector+0xd2/0x350 block/partitions/core.c:718 adfspart_check_POWERTEC+0x8d/0xf00 block/partitions/acorn.c:454 check_partition block/partitions/core.c:138 [inline] blk_add_partitions block/partitions/core.c:600 [inline] bdev_disk_changed+0x73a/0x1410 block/partitions/core.c:689 blkdev_get_whole+0x30d/0x390 block/bdev.c:672 blkdev_get_by_dev+0x279/0x600 block/bdev.c:814 blkdev_open+0x152/0x360 block/fops.c:589 do_dentry_open+0x8c6/0x1500 fs/open.c:929 do_open fs/namei.c:3640 [inline] path_openat+0x274b/0x3190 fs/namei.c:3797 do_filp_open+0x1c5/0x3d0 fs/namei.c:3824 do_sys_openat2+0x12c/0x1c0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe8890a7407 RSP: 002b:00007ffd3d3157b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fe889869880 RCX: 00007fe8890a7407 RDX: 00000000000a0800 RSI: 000056333d8bcb90 RDI: ffffffffffffff9c RBP: 000056333d89f910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000056333d8bcf10 R13: 000056333d8b7410 R14: 0000000000000000 R15: 000056333d8bcf10 Showing all locks held in the system: 1 lock held by khungtaskd/28: #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline] #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline] #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633 2 locks held by getty/5531: #0: ffff88803131a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900015d02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217 1 lock held by udevd/5778: #0: ffff88814130c4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805 6 locks held by kworker/0:0/11462: #0: ffff888147a78938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #0: ffff888147a78938 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #1: ffffc9000398fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline] #1: ffffc9000398fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711 #2: ffff888025019190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #2: ffff888025019190 (&dev->mutex){....}-{3:3}, at: hub_event+0x185/0x49c0 drivers/usb/core/hub.c:5861 #3: ffff88802501c508 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3215 [inline] #3: ffff88802501c508 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5426 [inline] #3: ffff88802501c508 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5669 [inline] #3: ffff88802501c508 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5833 [inline] #3: ffff88802501c508 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x21ab/0x49c0 drivers/usb/core/hub.c:5915 #4: ffff888024b2d668 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5427 [inline] #4: ffff888024b2d668 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5669 [inline] #4: ffff888024b2d668 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5833 [inline] #4: ffff888024b2d668 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x21d3/0x49c0 drivers/usb/core/hub.c:5915 #5: ffffffff8d8bf0f0 (ehci_cf_port_reset_rwsem){.+.+}-{3:3}, at: hub_port_reset+0x164/0x1740 drivers/usb/core/hub.c:3030 2 locks held by kworker/1:12/12271: 1 lock held by syz.1.2043/12949: #0: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline] #0: ffffffff8cd358f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004 1 lock held by syz.2.2040/12952: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x39b/0x3d0 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+0xf41/0xf80 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2938 Comm: kworker/u4:7 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:unwind_next_frame+0x16d9/0x2970 arch/x86/kernel/unwind_orc.c:641 Code: 00 00 43 0f b6 04 2e 84 c0 0f 85 37 0e 00 00 45 0f b7 37 41 c1 ee 04 41 83 e6 0f 4c 89 f7 48 c7 c6 e0 e7 b9 8c e8 67 db 4a 00 <41> 83 fe 04 0f 84 b8 00 00 00 41 83 fe 01 74 57 45 85 f6 0f 85 1b RSP: 0018:ffffc9000c5e7578 EFLAGS: 00000246 RAX: 0000000000000003 RBX: ffffffff8f22a5ea RCX: 0000000000000003 RDX: ffffffff813aba19 RSI: ffffffff8cb9e7e0 RDI: 0000000000000001 RBP: ffffc9000c5e7698 R08: ffff88802bde0000 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000000 R12: ffffc9000c5e7648 R13: dffffc0000000000 R14: 0000000000000001 R15: ffffffff8f22a5ee FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f459c9b7198 CR3: 000000000cb30000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000f80 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc_node_track_caller+0xb2/0x230 mm/slab_common.c:1027 kmalloc_reserve+0x116/0x240 net/core/skbuff.c:584 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:653 alloc_skb include/linux/skbuff.h:1284 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x293/0xb00 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 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