INFO: task udevd:4174 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:25216 pid: 4174 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 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: 0033:0x7fa0a7a4b407
RSP: 002b:00007ffc78464c70 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa0a795d880 RCX: 00007fa0a7a4b407
RDX: 00000000000a0800 RSI: 000055a9312bb150 RDI: ffffffffffffff9c
RBP: 000055a9312a9910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055a9312be830
R13: 000055a9312c1410 R14: 0000000000000000 R15: 000055a9312be830
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3951:
 #0: ffff88814cf12098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002d032e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
1 lock held by udevd/4174:
 #0: ffff8880207b4518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by syz-executor/4183:
3 locks held by kworker/u4:5/4270:
5 locks held by kworker/u4:7/4337:
 #0: ffff8880169cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000397fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d22c690 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:589
 #3: ffff88801fbcd3e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_destruct+0x112/0x300 drivers/net/wireguard/device.c:233
 #4: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #4: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by kworker/0:20/6656:
 #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000392fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
2 locks held by kworker/0:32/6670:
2 locks held by syz-executor/7789:
 #0: ffffffff8d238308 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d238308 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x974/0xe60 net/core/rtnetlink.c:5647
 #1: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #1: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by syz.4.893/7923:
 #0: ffff888020283518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff88802039d468 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:2071

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7923 Comm: syz.4.893 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:io_serial_in+0x73/0xb0 drivers/tty/serial/8250/8250_port.c:461
Code: e8 62 4f 32 fd 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 53 b7 76 fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 44 89 f9 80 e1 07 38 c1 7c aa 4c
RSP: 0018:ffffc9000446f078 EFLAGS: 00000006
RAX: 1ffffffff2c7d505 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000065476 RDI: 0000000000065477
RBP: ffffc9000446f250 R08: 0000000000000004 R09: 0000000000000003
R10: fffff5200088ddf0 R11: 1ffff9200088ddf0 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff963ea820 R15: 0000000000000000
FS:  00007fa312f186c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa314c941e0 CR3: 000000001f7fa000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 serial_port_in include/linux/serial_core.h:344 [inline]
 serial8250_console_write+0x241/0xf80 drivers/tty/serial/8250/8250_port.c:3367
 call_console_drivers kernel/printk/printk.c:-1 [inline]
 console_unlock+0xc86/0x1200 kernel/printk/printk.c:2744
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xcc/0x110 kernel/printk/printk.c:2299
 fat_msg+0x114/0x160 fs/fat/misc.c:56
 fat__get_entry fs/fat/dir.c:102 [inline]
 fat_get_entry+0x878/0xa90 fs/fat/dir.c:128
 fat_get_short_entry fs/fat/dir.c:873 [inline]
 fat_subdirs+0x113/0x220 fs/fat/dir.c:939
 fat_read_root+0x5c5/0x800 fs/fat/inode.c:1413
 fat_fill_super+0x33cb/0x48a0 fs/fat/inode.c:1863
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3025
 do_mount fs/namespace.c:3368 [inline]
 __do_sys_mount fs/namespace.c:3576 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3553
 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: 0033:0x7fa314cb266a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa312f17e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fa312f17ef0 RCX: 00007fa314cb266a
RDX: 0000200000000500 RSI: 0000200000000bc0 RDI: 00007fa312f17eb0
RBP: 0000200000000500 R08: 00007fa312f17ef0 R09: 0000000000000040
R10: 0000000000000040 R11: 0000000000000246 R12: 0000200000000bc0
R13: 00007fa312f17eb0 R14: 000000000000035f R15: 00002000000002c0
 </TASK>