INFO: task udevd:4394 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:23120 pid:4394  ppid:3638   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8799
 folio_wait_bit_common+0x877/0xfa0 mm/filemap.c:1324
 folio_put_wait_locked mm/filemap.c:1493 [inline]
 do_read_cache_folio+0x1a7/0x790 mm/filemap.c:3641
 read_mapping_folio include/linux/pagemap.h:799 [inline]
 read_part_sector+0xce/0x360 block/partitions/core.c:724
 adfspart_check_POWERTEC+0xc0/0x890 block/partitions/acorn.c:454
 check_partition block/partitions/core.c:146 [inline]
 blk_add_partitions block/partitions/core.c:609 [inline]
 bdev_disk_changed+0x7f9/0x1450 block/partitions/core.c:695
 blkdev_get_whole+0x2e8/0x370 block/bdev.c:700
 blkdev_get_by_dev+0x32e/0xa60 block/bdev.c:837
 blkdev_open+0x119/0x2d0 block/fops.c:500
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3791
 do_filp_open+0x1ee/0x420 fs/namei.c:3818
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1c684a7407
RSP: 002b:00007fffcd1ee880 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1c68b42880 RCX: 00007f1c684a7407
RDX: 00000000000a0800 RSI: 000055701424b620 RDI: ffffffffffffff9c
RBP: 000055701424a910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000557014267c00
R13: 0000557014258190 R14: 0000000000000000 R15: 0000557014267c00
 </TASK>
INFO: task udevd:4612 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:23120 pid:4612  ppid:3638   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8799
 folio_wait_bit_common+0x877/0xfa0 mm/filemap.c:1324
 folio_put_wait_locked mm/filemap.c:1493 [inline]
 do_read_cache_folio+0x1a7/0x790 mm/filemap.c:3641
 read_mapping_folio include/linux/pagemap.h:799 [inline]
 read_part_sector+0xce/0x360 block/partitions/core.c:724
 adfspart_check_POWERTEC+0xc0/0x890 block/partitions/acorn.c:454
 check_partition block/partitions/core.c:146 [inline]
 blk_add_partitions block/partitions/core.c:609 [inline]
 bdev_disk_changed+0x7f9/0x1450 block/partitions/core.c:695
 blkdev_get_whole+0x2e8/0x370 block/bdev.c:700
 blkdev_get_by_dev+0x32e/0xa60 block/bdev.c:837
 blkdev_open+0x119/0x2d0 block/fops.c:500
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3791
 do_filp_open+0x1ee/0x420 fs/namei.c:3818
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1c684a7407
RSP: 002b:00007fffcd1ee880 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1c68b42880 RCX: 00007f1c684a7407
RDX: 00000000000a0800 RSI: 000055701424b570 RDI: ffffffffffffff9c
RBP: 000055701424a910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000557014262e00
R13: 0000557014262410 R14: 0000000000000000 R15: 0000557014262e00
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
4 locks held by kworker/u4:3/46:
 #0: ffff88801761e938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000b77d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd4ead0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594
 #3: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: wg_destruct+0x21/0x300 drivers/net/wireguard/device.c:246
1 lock held by dhcpcd/3933:
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
2 locks held by getty/4025:
 #0: ffff888030027098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
1 lock held by udevd/4394:
 #0: ffff8881443dd4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x12a/0xa60 block/bdev.c:828
1 lock held by udevd/4612:
 #0: ffff888024d684c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x12a/0xa60 block/bdev.c:828
3 locks held by kworker/u4:9/6363:
4 locks held by kworker/u4:14/8994:
 #0: ffff8880b8f3ad18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x25/0x130 kernel/sched/core.c:538
 #1: ffff8880b8f27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x400/0x740 kernel/sched/psi.c:999
 #2: ffff8880b8f28458 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x123/0x270 kernel/time/timer.c:999
 #3: ffffffff96ea98c8 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x68/0x4f0 lib/debugobjects.c:747
3 locks held by kworker/0:10/12633:
 #0: ffff88814d0df938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000348fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x1500 net/ipv6/addrconf.c:4138
2 locks held by kworker/1:0/13386:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc9000db8fd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/u4:26/16416:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003e17d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
7 locks held by syz-executor/17853:
 #0: ffff88807e042460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x270/0x9a0 fs/read_write.c:580
 #1: ffff888020ea5488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1d8/0x520 fs/kernfs/file.c:343
 #2: ffff888144721bd0 (kn->active#54){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888144721bd0 (kn->active#54){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x520 fs/kernfs/file.c:344
 #3: ffffffff8d66a3a8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: new_device_store+0x139/0x690 drivers/net/netdevsim/bus.c:160
 #4: ffff8880289360e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:885 [inline]
 #4: ffff8880289360e8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x85/0x480 drivers/base/dd.c:1009
 #5: ffff8880796072f8 (&devlink->lock_key#15){+.+.}-{3:3}, at: nsim_drv_probe+0xc6/0xb20 drivers/net/netdevsim/dev.c:1542
 #6: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: nsim_init_netdevsim drivers/net/netdevsim/netdev.c:310 [inline]
 #6: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: nsim_create+0x312/0x400 drivers/net/netdevsim/netdev.c:365
2 locks held by syz.3.3487/18041:
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3495
 #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #1: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.5.3503/18112:
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x80d/0xfb0 net/core/rtnetlink.c:6163
1 lock held by syz.5.3503/18117:
 #0: ffffffff8dd5b968 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x2c8/0xe80 net/core/dev_ioctl.c:527

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

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 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 16 Comm: rcu_preempt Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__lock_release kernel/locking/lockdep.c:5381 [inline]
RIP: 0010:lock_release+0x2dc/0x920 kernel/locking/lockdep.c:5696
Code: 00 00 00 00 fc ff df 4c 8b 7c 24 18 0f 85 88 02 00 00 48 8b 44 24 40 42 0f b6 04 28 84 c0 0f 85 80 04 00 00 48 8b 04 24 89 10 <4c> 89 e0 48 c1 e8 03 42 80 3c 28 00 4c 8b 74 24 08 74 0e 4c 89 e7
RSP: 0018:ffffc90000157b80 EFLAGS: 00000046
RAX: ffff88813fef64d8 RBX: 1ffff11027fdeca0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8cb330d8 RDI: ffff88813fef64e0
RBP: ffffc90000157ca0 R08: ffffffff8e210aef R09: 1ffffffff1c4215d
R10: dffffc0000000000 R11: fffffbfff1c4215e R12: ffff88813fef64e0
R13: dffffc0000000000 R14: ffff88813fef6500 R15: 1ffff9200002af7c
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcfc267bf0 CR3: 0000000066b0b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
 _raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:186
 rcu_gp_init+0x517/0x14f0 kernel/rcu/tree.c:1524
 rcu_gp_kthread+0x18e/0x3b0 kernel/rcu/tree.c:1895
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>