syzbot

INFO: task syz-executor421:5865 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc2-syzkaller-00378-gb67ec639010f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor421 state:D stack:27312 pid:5865  tgid:5862  ppid:5861   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 super_lock+0x1c8/0x3b0 fs/super.c:115
 __iterate_supers+0x126/0x250 fs/super.c:923
 ksys_sync+0x94/0x150 fs/sync.c:102
 __ia32_sys_sync+0xe/0x20 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4f2aae77a9
RSP: 002b:00007f4f2aa7f218 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f4f2ab713f8 RCX: 00007f4f2aae77a9
RDX: 00007f4f2aae77a9 RSI: 0000000000000000 RDI: 0000000000000080
RBP: 00007f4f2ab713f0 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffd13efa757 R11: 0000000000000246 R12: 00007f4f2ab3e07c
R13: 0030656c69662f2e R14: 0000200000000440 R15: 00007ffd13efa758
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e33ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e33ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e33ee60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by getty/5596:
 #0: ffff8880356820a0 (&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-executor421/5863:
 #0: ffff888079d3e0e0 (&type->s_umount_key#41/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970 fs/super.c:345

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc2-syzkaller-00378-gb67ec639010f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 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:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.16.0-rc2-syzkaller-00378-gb67ec639010f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 19 1b 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e007d80 EFLAGS: 000002c6
RAX: 1b8e37af00c19600 RBX: ffffffff81978d58 RCX: 1b8e37af00c19600
RDX: 0000000000000001 RSI: ffffffff8da4bf83 RDI: ffffffff8be41940
RBP: ffffffff8e007ea8 R08: ffff8880b8632f5b R09: 1ffff110170c65eb
R10: dffffc0000000000 R11: ffffed10170c65ec R12: ffffffff8fc22df0
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1c12a50
FS:  0000000000000000(0000) GS:ffff888125a1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055bc6634d660 CR3: 000000000e138000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:749
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 rest_init+0x2de/0x300 init/main.c:745
 start_kernel+0x47d/0x500 init/main.c:1102
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x147
 </TASK>