INFO: task udevd:4175 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:22528 pid: 4175 ppid: 3562 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:731 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:616 [inline] bdev_disk_changed+0x917/0x16b0 block/partitions/core.c:702 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:3608 [inline] path_openat+0x2682/0x2f30 fs/namei.c:3742 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769 do_sys_openat2+0x142/0x4a0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1280 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: 0033:0x7fdc5ac17407 RSP: 002b:00007ffd04510290 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fdc5ab29880 RCX: 00007fdc5ac17407 RDX: 00000000000a0800 RSI: 000055f5a9e15fd0 RDI: ffffffffffffff9c RBP: 000055f5a9e08910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055f5a9e1cba0 R13: 000055f5a9e20410 R14: 0000000000000000 R15: 000055f5a9e1cba0 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c11c460 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 3 locks held by kworker/u4:2/154: #0: ffff8880169cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc90002077d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffffffff8d22bf10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:589 2 locks held by getty/3943: #0: ffff88802c00c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252 #1: ffffc900021ce2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158 1 lock held by udevd/4175: #0: ffff8880202bd918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820 1 lock held by udevd/4197: 4 locks held by kworker/1:17/4704: 5 locks held by kworker/0:18/6226: #0: ffff888141bf8d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1 #1: ffffc9000336fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285 #2: ffff888148237220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline] #2: ffff888148237220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x5560 drivers/usb/core/hub.c:5827 #3: ffff8880197f8220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline] #3: ffff8880197f8220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:954 #4: ffff88807e4c31a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline] #4: ffff88807e4c31a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x460 drivers/base/dd.c:954 4 locks held by udevd/6487: #0: ffff888023bc40a0 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xad/0xd50 fs/seq_file.c:182 #1: ffff88807a5acc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x51/0x3c0 fs/kernfs/file.c:112 #2: ffff888062a49a00 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x71/0x3c0 fs/kernfs/file.c:113 #3: ffff8880197f8220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline] #3: ffff8880197f8220 (&dev->mutex){....}-{3:3}, at: uevent_show+0x17a/0x330 drivers/base/core.c:2408 1 lock held by rm/10493: ============================================= 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 07/12/2025 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: 4387 Comm: kworker/u4:11 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:413 [inline] RIP: 0010:batadv_nc_worker+0x143/0x5c0 net/batman-adv/network-coding.c:723 Code: b3 97 f9 f7 eb 24 e8 ac 97 f9 f7 c6 05 3b b2 d7 03 01 48 c7 c7 a0 c5 1f 8b be e5 02 00 00 48 c7 c2 e0 c5 1f 8b e8 6d 12 20 00 <4c> 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8 a8 fd 3d f8 4d RSP: 0000:ffffc9000353fbe0 EFLAGS: 00000293 RAX: ffffffff897e32cb RBX: dffffc0000000000 RCX: ffff88807cf80000 RDX: 0000000000000000 RSI: ffffffff8a59a220 RDI: ffffffff8a59a1e0 RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1ff7619 R10: fffffbfff1ff7619 R11: 1ffffffff1ff7618 R12: 0000000000000257 R13: ffff8880771192b8 R14: ffff888074008c80 R15: ffff88814073b410 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd8116cc068 CR3: 0000000063bf9000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0x863/0x1000 kernel/workqueue.c:2310 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