INFO: task syz.3.1520:12810 blocked for more than 144 seconds.
      Not tainted 6.15.0-next-20250530-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1520      state:D stack:22792 pid:12810 tgid:12809 ppid:5838   task_flags:0x400140 flags:0x00004004
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: 0033:0x7f5f61b8e969
RSP: 002b:00007f5f62951038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f5f61db5fa0 RCX: 00007f5f61b8e969
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f5f61db5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5f61db5fa0 R15: 00007ffe55070f08
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13f140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13f140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by getty/5596:
 #0: ffff888030a0a0a0 (&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
3 locks held by kworker/1:6/7851:
1 lock held by syz.7.1513/12783:
 #0: ffff88802a2700e0 (&type->s_umount_key#117/1){+.+.}-{4:4}, at: alloc_super+0x204/0x970 fs/super.c:345
1 lock held by syz-executor/12989:
 #0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
 #0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:998
2 locks held by syz.4.1867/14351:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-next-20250530-syzkaller #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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 43 Comm: kworker/1:1 Not tainted 6.15.0-next-20250530-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_power_efficient gc_worker
RIP: 0010:__might_resched+0x8c/0x610 kernel/sched/core.c:8762
Code: 40 48 c1 eb 03 48 b8 f1 f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 09 f2 f2 f2 00 66 42 c7 44 2b 0d f3 f3 42 c6 44 2b 0f f3 <e8> 6f 72 d3 09 85 c0 74 46 48 c7 c7 a0 f1 13 8e be ff ff ff ff e8
RSP: 0018:ffffc90000b37800 EFLAGS: 00000a02
RAX: f2f2f200f1f1f1f1 RBX: 1ffff92000166f08 RCX: 650e3c3ce258d100
RDX: 0000000000000000 RSI: 0000000000000647 RDI: ffffffff8c97d940
RBP: ffffc90000b37910 R08: ffffffff8fa127f7 R09: 1ffffffff1f424fe
R10: dffffc0000000000 R11: fffffbfff1f424ff R12: ffff8880b873b080
R13: dffffc0000000000 R14: 0000000000038d1b R15: 0000000000071a37
FS:  0000000000000000(0000) GS:ffff888125d53000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdc4d3491c CR3: 0000000078108000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 gc_worker+0xbbe/0x1380 net/netfilter/nf_conntrack_core.c:1607
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 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>
vkms_vblank_simulate: vblank timer overrun