INFO: task syz.3.4142:20947 blocked for more than 143 seconds.
Not tainted syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.4142 state:D stack:26088 pid:20947 tgid:20939 ppid:18206 task_flags:0x40054c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
mmap_write_lock include/linux/mmap_lock.h:312 [inline]
exit_mmap+0x281/0xb20 mm/mmap.c:1288
__mmput+0x118/0x430 kernel/fork.c:1130
exit_mm+0x1da/0x2c0 kernel/exit.c:583
do_exit+0x658/0x2310 kernel/exit.c:961
do_group_exit+0x21c/0x2d0 kernel/exit.c:1114
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4f0 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+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f21df78f749
RSP: 002b:00007f21dd9f60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f21df9e6098 RCX: 00007f21df78f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f21df9e6098
RBP: 00007f21df9e6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f21df9e6128 R14: 00007fffd68100c0 R15: 00007fffd68101a8
INFO: task syz.6.4146:20951 blocked for more than 143 seconds.
Not tainted syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.4146 state:D stack:21336 pid:20951 tgid:20950 ppid:17912 task_flags:0x40054c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
mmap_write_lock include/linux/mmap_lock.h:312 [inline]
exit_mmap+0x281/0xb20 mm/mmap.c:1288
__mmput+0x118/0x430 kernel/fork.c:1130
exit_mm+0x1da/0x2c0 kernel/exit.c:583
do_exit+0x658/0x2310 kernel/exit.c:961
do_group_exit+0x21c/0x2d0 kernel/exit.c:1114
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4f0 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+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6c3d78f749
RSP: 002b:00007f6c3e5d10e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f6c3d9e5fa8 RCX: 00007f6c3d78f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6c3d9e5fa8
RBP: 00007f6c3d9e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6c3d9e6038 R14: 00007ffdcff6c3c0 R15: 00007ffdcff6c4a8
Showing all locks held in the system:
4 locks held by kworker/1:0/24:
1 lock held by khungtaskd/31:
#0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8df41cc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/0:2/180:
#0: ffff88801a055948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88801a055948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
#1: ffffc90002ff7b80 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90002ff7b80 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
#2: ffffffff8df477f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#2: ffffffff8df477f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:956
2 locks held by kworker/u8:7/1095:
2 locks held by getty/5589:
#0: ffff88814db4d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/17912:
#0: ffff88807d754cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline]
#0: ffff88807d754cc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288
1 lock held by syz-executor/17914:
#0: ffff8880494ff180 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline]
#0: ffff8880494ff180 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288
1 lock held by syz-executor/18202:
#0: ffff88807aecd900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline]
#0: ffff88807aecd900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288
1 lock held by syz-executor/18204:
#0: ffffffff8f2f5608 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f2f5608 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
1 lock held by syz.3.4142/20947:
#0: ffff888023a01bc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline]
#0: ffff888023a01bc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288
1 lock held by syz.6.4146/20951:
#0: ffff8880797f8340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:312 [inline]
#0: ffff8880797f8340 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x281/0xb20 mm/mmap.c:1288
1 lock held by syz-executor/21248:
5 locks held by syz-executor/21250:
#0: ffff888028340ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:499 [inline]
#0: ffff888028340ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x510 net/bluetooth/hci_core.c:2715
#1: ffff8880283400c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0xff0 net/bluetooth/hci_sync.c:5314
#2: ffffffff8f4672c8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2143 [inline]
#2: ffffffff8f4672c8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x230 net/bluetooth/hci_conn.c:2637
#3: ffff88806e077b38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x70/0x680 net/bluetooth/l2cap_core.c:1763
#4: ffffffff8df477f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#4: ffffffff8df477f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:956
1 lock held by syz-executor/21380:
=============================================
NMI backtrace for cpu 1
CPU: 1 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:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3c/0xf80 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 21380 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_preemption_disabled+0x40/0x120 lib/smp_processor_id.c:53
Code: 08 65 8b 05 26 92 2d 07 65 8b 0d 1b 92 2d 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d fb 91 2d 07 48 3b 4c 24 08 0f 85 cc 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 cc cc cc cc cc 48 c7 04 24 00 00
RSP: 0018:ffffc9001b74f948 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff888079a23d00 RCX: c8c11fa29f0db600
RDX: 0000000000000000 RSI: ffffffff8d780994 RDI: ffffffff8bbfc660
RBP: ffffc9001b74fa58 R08: ffffffff8f805a77 R09: 1ffffffff1f00b4e
R10: dffffc0000000000 R11: fffffbfff1f00b4f R12: dffffc0000000000
R13: ffff888035b45000 R14: ffffffff99b08100 R15: 1ffff920036e9f38
FS: 0000000000000000(0000) GS:ffff8881260b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563e661e1000 CR3: 000000000dd3a000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
lockdep_hardirqs_on_prepare+0xc3/0x290 kernel/locking/lockdep.c:4409
trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:78
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
_raw_spin_unlock_irqrestore+0x85/0x110 kernel/locking/spinlock.c:194
__debug_check_no_obj_freed lib/debugobjects.c:1108 [inline]
debug_check_no_obj_freed+0x52e/0x550 lib/debugobjects.c:1129
free_pages_prepare mm/page_alloc.c:1401 [inline]
__free_frozen_pages+0x4dd/0xd30 mm/page_alloc.c:2901
vfree+0x25a/0x400 mm/vmalloc.c:3440
kcov_put kernel/kcov.c:439 [inline]
kcov_close+0x28/0x50 kernel/kcov.c:535
__fput+0x44c/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6c5/0x2310 kernel/exit.c:973
do_group_exit+0x21c/0x2d0 kernel/exit.c:1114
__do_sys_exit_group kernel/exit.c:1125 [inline]
__se_sys_exit_group kernel/exit.c:1123 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1123
x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbec2d8f749
Code: Unable to access opcode bytes at 0x7fbec2d8f71f.
RSP: 002b:00007ffca0567708 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fbec2e1585d RCX: 00007fbec2d8f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007fbec2e1586f R08: 00007ffca05654a7 R09: 00000000000927c0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
R13: 00000000000927c0 R14: 00000000000a289e R15: 00007ffca05678b0