INFO: task syz.3.4532:13510 blocked for more than 122 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.4532 state:D stack:0 pid:13510 tgid:13508 ppid:13374 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5945 [inline]
__schedule+0x1322/0x1df0 kernel/sched/core.c:7791
__schedule_loop kernel/sched/core.c:7872 [inline]
schedule+0xc6/0x240 kernel/sched/core.c:7887
request_wait_answer fs/fuse/dev.c:476 [inline]
__fuse_request_send fs/fuse/dev.c:491 [inline]
__fuse_simple_request+0xdb1/0x1980 fs/fuse/dev.c:586
fuse_simple_request fs/fuse/fuse_i.h:1248 [inline]
fuse_rmdir+0x2c7/0x1a50 fs/fuse/dir.c:1290
vfs_rmdir+0x3dd/0x560 fs/namei.c:4340
do_rmdir+0x26a/0x560 fs/namei.c:4399
__do_sys_rmdir fs/namei.c:4418 [inline]
__se_sys_rmdir fs/namei.c:4416 [inline]
__x64_sys_rmdir+0x4b/0x60 fs/namei.c:4416
x64_sys_call+0xaf7/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:85
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f34f498eec9
RSP: 002b:00007f34f585e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00007f34f4be6090 RCX: 00007f34f498eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000040
RBP: 00007f34f4a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f34f4be6128 R14: 00007f34f4be6090 R15: 00007ffdf384dc78
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 ad4feab416e89c88ed6525c0702811b15fc9e1bf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:94
dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
dump_stack+0x19/0x20 lib/dump_stack.c:129
nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
watchdog+0xd8f/0xed0 kernel/hung_task.c:423
kthread+0x2ca/0x370 kernel/kthread.c:389
ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted syzkaller #0 ad4feab416e89c88ed6525c0702811b15fc9e1bf
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: usb_hub_wq hub_event
RIP: 0010:io_serial_in+0x7b/0xc0 drivers/tty/serial/8250/8250_port.c:406
Code: e8 aa 05 6d fe 44 89 f9 d3 e3 49 83 c6 08 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 0b 73 c3 fe 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f 5d e9 c5 a9 76 02 cc 44 89 f9 80 e1
RSP: 0018:ffffc900000a7010 EFLAGS: 00000002
RAX: 1ffffffff113e960 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 000000000002c2cd RDI: 000000000002c2ce
RBP: ffffc900000a7030 R08: ffff888101ab8107 R09: 1ffff11020357020
R10: 0000000000000000 R11: ffffffff8318f050 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff889f4e28 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd847b7e38 CR3: 000000010bf4e000 CR4: 00000000003526b0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:137 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]
wait_for_lsr drivers/tty/serial/8250/8250_port.c:2069 [inline]
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3314 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3336 [inline]
serial8250_console_write+0x1395/0x2130 drivers/tty/serial/8250/8250_port.c:3421
univ8250_console_write+0x6f/0xb0 drivers/tty/serial/8250/8250_core.c:396
console_emit_next_record kernel/printk/printk.c:3151 [inline]
console_flush_all+0x5e3/0xaa0 kernel/printk/printk.c:3239
__console_flush_and_unlock kernel/printk/printk.c:3298 [inline]
console_unlock+0xe9/0x270 kernel/printk/printk.c:3338
vprintk_emit+0x27c/0x640 kernel/printk/printk.c:2462
dev_vprintk_emit+0x33b/0x400 drivers/base/core.c:4962
dev_printk_emit+0xe1/0x130 drivers/base/core.c:4973
__dev_printk+0x17f/0x1b0 drivers/base/core.c:4985
_dev_info+0x10b/0x160 drivers/base/core.c:5031
hub_port_init+0x5fb/0x27b0 drivers/usb/core/hub.c:4990
hub_port_connect drivers/usb/core/hub.c:5490 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5701 [inline]
port_event drivers/usb/core/hub.c:5865 [inline]
hub_event+0x232d/0x4270 drivers/usb/core/hub.c:5947
process_one_work kernel/workqueue.c:3237 [inline]
process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3318
worker_thread+0xc58/0x1250 kernel/workqueue.c:3399
kthread+0x2ca/0x370 kernel/kthread.c:389
ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244