syzbot

INFO: task udevd:11976 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:23576 pid:11976 tgid:11976 ppid:5219   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 io_schedule+0xbf/0x130 kernel/sched/core.c:7903
 folio_wait_bit_common+0x3d6/0x9e0 mm/filemap.c:1317
 folio_put_wait_locked mm/filemap.c:1481 [inline]
 do_read_cache_folio+0x342/0x5c0 mm/filemap.c:3939
 read_mapping_folio include/linux/pagemap.h:991 [inline]
 read_part_sector+0xd4/0x370 block/partitions/core.c:722
 adfspart_check_POWERTEC+0x8a/0x710 block/partitions/acorn.c:454
 check_partition block/partitions/core.c:141 [inline]
 blk_add_partitions block/partitions/core.c:589 [inline]
 bdev_disk_changed+0x720/0x1520 block/partitions/core.c:693
 blkdev_get_whole+0x187/0x290 block/bdev.c:748
 bdev_open+0x2c7/0xe40 block/bdev.c:957
 blkdev_open+0x277/0x3f0 block/fops.c:691
 do_dentry_open+0x982/0x1530 fs/open.c:965
 vfs_open+0x82/0x3f0 fs/open.c:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4046
 do_filp_open+0x20b/0x470 fs/namei.c:4073
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1461
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f36fcca7407
RSP: 002b:00007fffedfe5a40 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f36fd45d880 RCX: 00007f36fcca7407
RDX: 00000000000a0800 RSI: 000055f8e6a52930 RDI: ffffffffffffff9c
RBP: 000055f8e680c2c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055f8e6a574e0
R13: 000055f8e6a478d0 R14: 0000000000000000 R15: 000055f8e6a574e0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by getty/5605:
 #0: ffff88814dc9e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
4 locks held by kworker/u8:17/7695:
 #0: ffff88801b881148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
 #1: ffffc900058dfd10 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
 #2: ffffffff90382ac8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:303
 #3: ffffffff8e5cc7b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311
1 lock held by udevd/11976:
 #0: ffff888143752358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945
3 locks held by kworker/u8:3/19636:
 #0: ffff88801dbf8948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211
 #1: ffffc90004b5fd10 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212
 #2: ffffffff90382ac8 (rtnl_mutex){+.+.}-{4:4}, at: cfg80211_dfs_channels_update_work+0xcf/0x640 net/wireless/mlme.c:1040

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
 watchdog+0xf0e/0x1260 kernel/hung_task.c:491
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 4c 62 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 52 16 00 fb f4 <e9> 4c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df8 EFLAGS: 000002c2
RAX: 0000000003fffe19 RBX: 0000000000000001 RCX: ffffffff8b93bc29
RDX: 0000000000000000 RSI: ffffffff8de4fd50 RDI: ffffffff8c162900
RBP: ffffed1003c5d488 R08: 0000000000000001 R09: ffffed10170a6655
R10: ffff8880b85332ab R11: 0000000000000000 R12: 0000000000000001
R13: ffff88801e2ea440 R14: ffffffff90ab4390 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881247bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe9bfafff8 CR3: 000000006327c000 CR4: 00000000003526f0
DR0: 000000000000000a DR1: 0000000000000002 DR2: 0000000000000004
DR3: 0000000000000003 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x148
 </TASK>