INFO: task syz.8.5992:18503 blocked for more than 122 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.5992 state:D stack:0 pid:18503 tgid:18502 ppid:17781 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_lookup_name+0x2db/0x990 fs/fuse/dir.c:526
fuse_lookup+0x2ad/0x18f0 fs/fuse/dir.c:624
__lookup_slow+0x2d7/0x400 fs/namei.c:1732
lookup_slow+0x57/0x80 fs/namei.c:1749
walk_component+0x302/0x440 fs/namei.c:2053
lookup_last fs/namei.c:2556 [inline]
path_lookupat+0x180/0x4a0 fs/namei.c:2580
filename_lookup+0x428/0x520 fs/namei.c:2611
do_readlinkat+0xda/0x510 fs/stat.c:537
__do_sys_readlink fs/stat.c:574 [inline]
__se_sys_readlink fs/stat.c:571 [inline]
__x64_sys_readlink+0x83/0xa0 fs/stat.c:571
x64_sys_call+0x155b/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:90
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: 0033:0x7fedf498eec9
RSP: 002b:00007fedf577b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007fedf4be5fa0 RCX: 00007fedf498eec9
RDX: 0000000000000097 RSI: 00002000000021c0 RDI: 0000200000002000
RBP: 00007fedf4a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fedf4be6038 R14: 00007fedf4be5fa0 R15: 00007ffc998b5428
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 658fd523d4664e50339751640158cdc1077a64d7
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 872 Comm: kworker/1:4 Not tainted syzkaller #0 658fd523d4664e50339751640158cdc1077a64d7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: usb_hub_wq hub_event
RIP: 0010:io_serial_out+0x85/0xd0 drivers/tty/serial/8250/8250_port.c:413
Code: fe 44 89 e1 41 d3 e6 49 83 c7 08 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 e4 76 c3 fe 45 03 37 89 d8 44 89 f2 ee <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 e1 80 e1 07
RSP: 0018:ffffc9000e9b7008 EFLAGS: 00000002
RAX: 0000000000000031 RBX: 0000000000000031 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000005e653 RDI: 000000000005e654
RBP: ffffc9000e9b7030 R08: ffff888107eb0107 R09: 1ffff11020fd6020
R10: 0000000000000000 R11: ffffffff8318dc60 R12: 0000000000000000
R13: dffffc0000000000 R14: 00000000000003f8 R15: ffffffff889f3e28
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2df1eff8 CR3: 000000010b7e0000 CR4: 00000000003526b0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
serial_out drivers/tty/serial/8250/8250.h:142 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
serial8250_console_write+0x166d/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:3152 [inline]
console_flush_all+0x5e6/0xaa0 kernel/printk/printk.c:3240
__console_flush_and_unlock kernel/printk/printk.c:3299 [inline]
console_unlock+0xe9/0x270 kernel/printk/printk.c:3339
vprintk_emit+0x27c/0x640 kernel/printk/printk.c:2463
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_err+0x10b/0x160 drivers/base/core.c:5028
hub_port_init+0x1297/0x27b0 drivers/usb/core/hub.c:-1
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:3238 [inline]
process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3319
worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
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