INFO: task syz.7.6802:20974 blocked for more than 122 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.6802 state:D stack:0 pid:20974 tgid:20973 ppid:19156 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
super_lock+0x150/0x300 fs/super.c:115
super_lock_shared fs/super.c:140 [inline]
iterate_supers+0x8a/0x560 fs/super.c:934
ksys_sync+0x95/0x160 fs/sync.c:103
__ia32_sys_sync+0x12/0x20 fs/sync.c:114
x64_sys_call+0x2a58/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:163
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: 0033:0x7f8166d8f6c9
RSP: 002b:00007f8167b8a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f8166fe5fa0 RCX: 00007f8166d8f6c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f8166fe5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8166fe6038 R14: 00007f8166fe5fa0 R15: 00007ffde046bc08
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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: 26306 Comm: syz.4.8571 Not tainted syzkaller #0 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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 94 61 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:ffffc90003b0ef28 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000018f95 RDI: 0000000000018f96
RBP: ffffc90003b0ef50 R08: 0000000000000003 R09: 0000000000000004
R10: 0000000000000000 R11: ffffffff83190a20 R12: 0000000000000000
R13: dffffc0000000000 R14: 00000000000003f9 R15: ffffffff889f5fe8
FS: 00007f96ebe3f6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000014fd96000 CR4: 00000000003526b0
Call Trace:
serial_out drivers/tty/serial/8250/8250.h:142 [inline]
serial8250_clear_IER drivers/tty/serial/8250/8250_port.c:-1 [inline]
serial8250_console_write+0x3a9/0x2130 drivers/tty/serial/8250/8250_port.c:3386
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+0x5e6/0xaa0 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
vprintk_default+0x2a/0x40 kernel/printk/printk.c:2477
vprintk+0x93/0xa0 kernel/printk/printk_safe.c:73
_printk+0xd0/0x120 kernel/printk/printk.c:2487
p9_errstr2errno+0x19a/0x200 net/9p/error.c:223
p9_check_errors+0x4c1/0x6b0 net/9p/client.c:559
p9_client_rpc+0x721/0xb40 net/9p/client.c:756
p9_client_attach+0x170/0x5b0 net/9p/client.c:1125
v9fs_session_init+0x137c/0x1820 fs/9p/v9fs.c:459
v9fs_mount+0xd7/0xa00 fs/9p/vfs_super.c:122
legacy_get_tree+0x106/0x1b0 fs/fs_context.c:662
vfs_get_tree+0x9e/0x290 fs/super.c:1817
do_new_mount+0x251/0xb40 fs/namespace.c:3537
path_mount+0x688/0x1050 fs/namespace.c:3864
do_mount fs/namespace.c:3877 [inline]
__do_sys_mount fs/namespace.c:4087 [inline]
__se_sys_mount+0x2bd/0x480 fs/namespace.c:4064
__x64_sys_mount+0xc3/0xf0 fs/namespace.c:4064
x64_sys_call+0x2021/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:166
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: 0033:0x7f96eaf8f6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f96ebe3f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f96eb1e5fa0 RCX: 00007f96eaf8f6c9
RDX: 0000200000000180 RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007f96eb011f91 R08: 0000200000000080 R09: 0000000000000000
R10: 0000000002004000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f96eb1e6038 R14: 00007f96eb1e5fa0 R15: 00007fff9cb2b818