INFO: task syz.1.278:9326 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 >[ 490.784214][ T38] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.278 state:D stack:25624 pid:9326 tgid:9325 ppid:5798 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x145f/0x5070 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153
kthread_flush_worker+0x10e/0x160 kernel/kthread.c:1559
__alloc_workqueue+0x1485/0x1b80 kernel/workqueue.c:5797
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5820
btrfs_init_workqueues+0x25e/0x680 fs/btrfs/disk-io.c:1978
open_ctree+0x141d/0x3d20 fs/btrfs/disk-io.c:3411
btrfs_fill_super fs/btrfs/super.c:981 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1944 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline]
btrfs_get_tree+0x1061/0x1920 fs/btrfs/super.c:2121
vfs_get_tree+0x92/0x2a0 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f960fbd0eea
RSP: 002b:00007f960de35e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f960de35ef0 RCX: 00007f960fbd0eea
RDX: 00002000000055c0 RSI: 0000200000000000 RDI: 00007f960de35eb0
RBP: 00002000000055c0 R08: 00007f960de35ef0 R09: 000000000300000a
R10: 000000000300000a R11: 0000000000000246 R12: 0000200000000000
R13: 00007f960de35eb0 R14: 00000000000055a3 R15: 0000200000000080
Showing all locks held in the system:
7 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/38:
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:5/82:
1 lock held by udevd/5169:
2 locks held by getty/5558:
#0: ffff8880346d50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x44f/0x1460 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5799:
#0: ffffffff8d20c0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:37 [inline]
#0: ffffffff8d20c0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xe1/0x740 kernel/exit.c:1672
2 locks held by syz-executor/5800:
1 lock held by syz.1.278/9326:
#0: ffff88802ebd00d0 (&type->s_umount_key#54/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
3 locks held by kworker/u8:24/10221:
1 lock held by syz-executor/10902:
#0: ffff888032a400d0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff888032a400d0 (&type->s_umount_key#57){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff888032a400d0 (&type->s_umount_key#57){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
2 locks held by syz-executor/11269:
#0: ffffffff8e8989c0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x3cc/0x570 net/core/net_namespace.c:577
#1: ffffffff8e8a5df8 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x2ab/0x800 net/ipv4/ip_tunnel.c:1146
4 locks held by syz.2.454/11278:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 ee b3 b5 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ef ed 17 fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000167950 EFLAGS: 00000202
RAX: 1ffffffff31f3b00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffffff98f9e010 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8509f8e0 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff98f9dd80 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126dec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000032a0 CR3: 0000000029afa000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1961
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline]
serial8250_console_write+0x11bd/0x1b40 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3109 [inline]
console_flush_one_record+0x685/0xb80 kernel/printk/printk.c:3215
legacy_kthread_func+0x16f/0x210 kernel/printk/printk.c:3674
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246