Kernel bug: INFO: task hung in vfs_coredump (2)
Subsystem: kernel
Status: open

Crash report:
INFO: task syz.0.17:6012 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:28120 pid:6012  tgid:6010  ppid:5963   task_flags:0x400640 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion_state+0x1c/0x40 kernel/sched/completion.c:269
 coredump_wait fs/coredump.c:534 [inline]
 vfs_coredump+0x848/0x55e0 fs/coredump.c:1196
 get_signal+0x22e1/0x26d0 kernel/signal.c:3019
 arch_do_signal_or_restart+0x8f/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f182c18f7c9
RSP: 002b:00007f182d0da0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f182c3e6098 RCX: 00007f182c18f7c9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f182c3e609c
RBP: 00007f182c3e6090 R08: 00007f182d0fc000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f182c3e6128 R14: 00007fff44638a70 R15: 00007fff44638b58
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8e3c9520 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
3 locks held by kworker/u9:1/5151:
 #0: ffff88807c6b9148 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232
 #1: ffffc9000ef27c90 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233
 #2: ffff8880340b8ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x470 net/bluetooth/hci_sync.c:331
2 locks held by getty/5590:
 #0: ffff88814d06b0a0 (&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/0x1510 drivers/tty/n_tty.c:2211
1 lock held by syz.0.17/6011:
1 lock held by syz.1.18/6037:
1 lock held by syz.2.19/6067:
1 lock held by syz.3.20/6093:
1 lock held by syz.4.21/6124:
1 lock held by syz.5.22/6163:
1 lock held by syz.6.23/6196:
1 lock held by syz.7.24/6230:

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

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 10/25/2025
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]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x133/0x180 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xe66/0x1180 kernel/hung_task.c:515
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 74 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:__lock_acquire+0x155/0x2890 kernel/locking/lockdep.c:5170
Code: 1e 4b 8d 74 1e d8 0f b7 46 20 25 ff 1f 00 00 44 39 c8 75 0b 48 83 3c 24 00 0f 85 be 03 00 00 4d 01 de 44 89 ca 41 0f b7 46 20 <66> 81 e2 ff 1f 4d 89 6e 10 66 25 00 e0 09 d0 66 41 89 46 20 48 8b
RSP: 0018:ffffc9000218f308 EFLAGS: 00000086
RAX: 0000000000000007 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000007 RSI: ffff88801cbc2a00 RDI: ffffffff8e3c9520
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000007
R10: 0000000000000002 R11: ffff88801cbc29b0 R12: ffff88801cbc1e80
R13: ffffffff8e3c9520 R14: ffff88801cbc2a28 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881249fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005633703e3320 CR3: 000000000e184000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kfree+0x2f8/0x6e0 mm/slub.c:6878
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1576 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x1ab4/0x2fc0 net/mac80211/ibss.c:1602
 ieee80211_iface_process_skb net/mac80211/iface.c:1736 [inline]
 ieee80211_iface_work+0xe28/0x1350 net/mac80211/iface.c:1790
 cfg80211_wiphy_work+0x3fb/0x560 net/wireless/core.c:438
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>