syzbot

INFO: task syz.0.20:4451 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.20        state:D stack:27856 pid:4451  ppid:4400   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6697
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x562/0xaf0 kernel/locking/mutex.c:747
 blkdev_put+0xfe/0x710 block/bdev.c:930
 blkdev_close+0x51/0x80 block/fops.c:514
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 get_signal+0x11a6/0x1350 kernel/signal.c:2648
 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f21e939ce59
RSP: 002b:00007f21ea25b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f21e9615fa0 RCX: 00007f21e939ce59
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005
RBP: 00007f21e9432d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f21e9616038 R14: 00007f21e9615fa0 R15: 00007fffd2201178
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e770 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2ef90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
 #0: ffffffff8cb2dde0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2dde0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2dde0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4030:
 #0: ffff88814cbdd098 (&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+0x429/0x1390 drivers/tty/n_tty.c:2198
1 lock held by udevd/4407:
 #0: ffff888024d2a4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
1 lock held by udevd/4409:
 #0: ffff888024bcd4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
1 lock held by udevd/4410:
 #0: ffff888024d054c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
1 lock held by udevd/4412:
 #0: ffff888024d004c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
1 lock held by udevd/4413:
 #0: ffff888024d2f4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832
1 lock held by syz.0.20/4451:
 #0: ffff888024bcd4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfe/0x710 block/bdev.c:930
1 lock held by syz.1.30/4485:
 #0: ffff888024d004c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfe/0x710 block/bdev.c:930
1 lock held by syz.2.52/4555:
 #0: ffff888024d054c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfe/0x710 block/bdev.c:930
1 lock held by syz.3.82/4629:
 #0: ffff888024d2a4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfe/0x710 block/bdev.c:930
1 lock held by syz.4.90/4670:
 #0: ffff888024d2f4c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfe/0x710 block/bdev.c:930
1 lock held by syz.5.92/4692:
 #0: ffff888024e144c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xfe/0x710 block/bdev.c:930
1 lock held by udevd/4693:
 #0: ffff888024e144c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x13d/0xa60 block/bdev.c:832

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

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 04/18/2026
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+0xeee/0xf30 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: 56 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:125 [inline]
RIP: 0010:lockdep_hardirqs_off+0x48/0x100 kernel/locking/lockdep.c:4407
Code: 90 00 00 00 48 89 fb 65 8b 05 ec 67 d4 75 a9 00 00 f0 00 74 68 83 3d d6 09 92 0c 00 75 15 48 c7 04 24 00 00 00 00 9c 8f 04 24 <f7> 04 24 00 02 00 00 75 79 65 8b 05 e8 6e d4 75 85 c0 74 56 65 4c
RSP: 0018:ffffc90001587088 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffffff8a381c0b RCX: 55b44558e0f4cc00
RDX: 0000000000000000 RSI: ffffffff8a8c19c0 RDI: ffffffff8adf1ba0
RBP: ffffc90001587150 R08: ffffffff90afa307 R09: 1ffffffff215f460
R10: dffffc0000000000 R11: fffffbfff215f461 R12: dffffc0000000000
R13: ffff8880258d9f80 R14: 0000000000000a06 R15: 1ffff920002b0e18
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558942d4e8 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 trace_hardirqs_off+0xe/0x40 kernel/trace/trace_preemptirq.c:76
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
 _raw_spin_lock_irqsave+0x8b/0x100 kernel/locking/spinlock.c:162
 debug_object_active_state+0x6a/0x380 lib/debugobjects.c:926
 debug_rcu_head_queue kernel/rcu/rcu.h:191 [inline]
 kvfree_call_rcu+0xc6/0x870 kernel/rcu/tree.c:3396
 cfg80211_update_known_bss+0x178/0xa20 net/wireless/scan.c:-1
 cfg80211_bss_update+0x15f/0x2250 net/wireless/scan.c:1847
 cfg80211_inform_single_bss_frame_data net/wireless/scan.c:2506 [inline]
 cfg80211_inform_bss_frame_data+0x9ec/0x1390 net/wireless/scan.c:2539
 ieee80211_bss_info_update+0x738/0xc80 net/mac80211/scan.c:190
 ieee80211_rx_bss_info net/mac80211/ibss.c:1120 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x189d/0x2cd0 net/mac80211/ibss.c:1638
 ieee80211_iface_process_skb net/mac80211/iface.c:1679 [inline]
 ieee80211_iface_work+0x726/0xc80 net/mac80211/iface.c:1733
 cfg80211_wiphy_work+0x221/0x260 net/wireless/core.c:433
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>