syzbot

INFO: task udevd:7376 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:25712 pid:7376  ppid:5140   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 io_schedule+0x80/0xd0 kernel/sched/core.c:9023
 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:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7efc810a7407
RSP: 002b:00007fff99411790 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007efc817cd880 RCX: 00007efc810a7407
RDX: 00000000000a0800 RSI: 00005605c031da70 RDI: ffffffffffffff9c
RBP: 00005605c02f9910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005605c0311e00
R13: 00005605c0311410 R14: 0000000000000000 R15: 00005605c0311e00
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2ffa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2ffa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2ffa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/u4:4/59:
2 locks held by kworker/u4:5/144:
3 locks held by kworker/u4:11/3501:
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017871538 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc9000cef7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc9000cef7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #2: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:286
2 locks held by dhcpcd/5435:
 #0: ffff8880182f7690 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: netlink_dump+0xcc/0xde0 net/netlink/af_netlink.c:2200
 #1: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0x71f/0xde0 net/netlink/af_netlink.c:2263
2 locks held by getty/5528:
 #0: ffff88802d6490a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000326e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
2 locks held by kworker/1:7/5853:
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #0: ffff888017872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
 #1: ffffc90004b8fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2609 [inline]
 #1: ffffc90004b8fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x957/0x15b0 kernel/workqueue.c:2711
1 lock held by udevd/7376:
 #0: ffff888021e5a4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:805
2 locks held by syz.2.1590/13885:
 #0: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x41/0x1c0 drivers/net/tun.c:3511
 #1: ffffffff8cd35978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #1: ffffffff8cd35978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x448/0x830 kernel/rcu/tree_exp.h:1004
1 lock held by syz.8.1592/13919:
 #0: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3b9/0x1fd0 drivers/net/tun.c:3121
1 lock held by syz.8.1592/13920:
 #0: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3b9/0x1fd0 drivers/net/tun.c:3121
1 lock held by syz.8.1592/13923:
 #0: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3b9/0x1fd0 drivers/net/tun.c:3121
3 locks held by syz.8.1592/13927:
 #0: ffffffff8e01acd0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1074
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_op_lock net/netlink/genetlink.c:58 [inline]
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x10e/0x790 net/netlink/genetlink.c:1065
 #2: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: __tipc_nl_compat_doit net/tipc/netlink_compat.c:358 [inline]
 #2: ffffffff8dfb6208 (rtnl_mutex){+.+.}-{3:3}, at: tipc_nl_compat_doit+0x1fe/0x5e0 net/tipc/netlink_compat.c:393
2 locks held by syz.5.1594/13929:
 #0: ffffffff8e01acd0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1074
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_op_lock net/netlink/genetlink.c:58 [inline]
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x10e/0x790 net/netlink/genetlink.c:1065
2 locks held by syz.0.1596/13936:
 #0: ffffffff8e01acd0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1074
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_op_lock net/netlink/genetlink.c:58 [inline]
 #1: ffffffff8e01aae8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x10e/0x790 net/netlink/genetlink.c:1065

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7162 Comm: kworker/0:8 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_power_efficient wg_ratelimiter_gc_entries
RIP: 0010:__lock_release kernel/locking/lockdep.c:5458 [inline]
RIP: 0010:lock_release+0x2b2/0x8b0 kernel/locking/lockdep.c:5774
Code: 85 a9 04 00 00 45 89 2e 45 85 ff 49 bd 00 00 00 00 00 fc ff df 4c 8b 7c 24 08 0f 85 84 02 00 00 48 8b 44 24 20 42 0f b6 04 28 <84> c0 0f 85 56 04 00 00 48 8b 04 24 89 10 4c 89 e0 48 c1 e8 03 42
RSP: 0018:ffffc900032e7a40 EFLAGS: 00000087
RAX: 0000000000000000 RBX: 1ffff1100496d52a RCX: 0000000000000001
RDX: 0000000000000002 RSI: ffffffff8d766b58 RDI: ffff888024b6a930
RBP: ffffc900032e7b48 R08: ffffffff8e4a39ef R09: 1ffffffff1c9473d
R10: dffffc0000000000 R11: fffffbfff1c9473e R12: ffff888024b6a930
R13: dffffc0000000000 R14: ffff888024b6a950 R15: 1ffff9200065cf54
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8ab3e7ee9c CR3: 000000002d2e3000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
 _raw_spin_unlock+0x16/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 wg_ratelimiter_gc_entries+0x384/0x450 drivers/net/wireguard/ratelimiter.c:76
 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
 </TASK>