INFO: task udevd:5067 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:24800 pid: 5067 ppid: 3561 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503 wait_on_page_bit_common+0x815/0xe00 mm/filemap.c:1356 wait_on_page_bit mm/filemap.c:1417 [inline] wait_on_page_locked include/linux/pagemap.h:688 [inline] wait_on_page_read mm/filemap.c:3437 [inline] do_read_cache_page+0xb05/0x1030 mm/filemap.c:3480 read_mapping_page include/linux/pagemap.h:515 [inline] read_part_sector+0xd4/0x4f0 block/partitions/core.c:726 adfspart_check_ICS+0xbf/0xe00 block/partitions/acorn.c:360 check_partition block/partitions/core.c:148 [inline] blk_add_partitions block/partitions/core.c:611 [inline] bdev_disk_changed+0x917/0x16b0 block/partitions/core.c:697 blkdev_get_whole+0x2f9/0x390 block/bdev.c:682 blkdev_get_by_dev+0x2d0/0xa60 block/bdev.c:827 blkdev_open+0x12d/0x2c0 block/fops.c:466 do_dentry_open+0x7ff/0xf80 fs/open.c:826 do_open fs/namei.c:3616 [inline] path_openat+0x2682/0x2f30 fs/namei.c:3750 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777 do_sys_openat2+0x142/0x4a0 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fea20864407 RSP: 002b:00007fff5f2908b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fea20776880 RCX: 00007fea20864407 RDX: 00000000000a0800 RSI: 0000557a68201320 RDI: ffffffffffffff9c RBP: 0000557a681e4910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000557a681f8fa0 R13: 0000557a681fc410 R14: 0000000000000000 R15: 0000557a681f8fa0 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 2 locks held by kworker/u5:0/146: #0: ffff888147900938 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc9000173fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 1 lock held by udevd/3561: #0: ffff888020636918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820 2 locks held by getty/3955: #0: ffff88814cdcd098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158 1 lock held by udevd/5067: #0: ffff888020636918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820 1 lock held by syz.0.58/5149: #0: ffff888020636918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915 1 lock held by syz-executor/5151: #0: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475 1 lock held by syz.1.208/5502: #0: ffff888020732208 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x140/0xe40 drivers/block/nbd.c:1460 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 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+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe0f/0xe50 kernel/hung_task.c:369 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3088 Comm: kworker/u4:5 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: phy9 ieee80211_iface_work RIP: 0010:task_css_set include/linux/cgroup.h:483 [inline] RIP: 0010:task_dfl_cgroup include/linux/cgroup.h:552 [inline] RIP: 0010:cgroup_account_cputime include/linux/cgroup.h:796 [inline] RIP: 0010:update_curr+0x3ba/0x8c0 kernel/sched/fair.c:858 Code: 12 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 77 44 67 00 48 8b 1b e8 bf fc 4c 08 85 c0 74 61 e8 16 0e 0e 00 <85> c0 75 58 48 c7 c7 c8 1f 14 8c be ff ff ff ff e8 51 f9 4c 08 85 RSP: 0018:ffffc9000d69f9b8 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffffffff8c144780 RCX: c5f9ee5d2476dd00 RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800 RBP: 0000000c0b18467d R08: dffffc0000000000 R09: fffffbfff1ad26b6 R10: fffffbfff1ad26b6 R11: 1ffffffff1ad26b5 R12: ffff8880b903a428 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802acada00 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f93e307ef98 CR3: 000000007a763000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: enqueue_entity+0xca/0x1e50 kernel/sched/fair.c:4468 enqueue_task_fair+0x183/0x16a0 kernel/sched/fair.c:5824 enqueue_task+0x182/0x2b0 kernel/sched/core.c:1996 activate_task kernel/sched/core.c:2024 [inline] ttwu_do_activate+0x1b7/0x370 kernel/sched/core.c:3633 ttwu_queue kernel/sched/core.c:3842 [inline] try_to_wake_up+0x618/0x1050 kernel/sched/core.c:4165 wake_up_worker kernel/workqueue.c:859 [inline] process_one_work+0x69c/0x1000 kernel/workqueue.c:2273 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287