INFO: task syz.2.3106:15143 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.3106      state:D stack:26568 pid:15143 tgid:15142 ppid:13013  task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5360 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7046 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7061
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118
 __mutex_lock_common kernel/locking/mutex.c:676 [inline]
 __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
 sync_bdevs+0x1ac/0x340 block/bdev.c:1288
 ksys_sync+0xb9/0x150 fs/sync.c:105
 __ia32_sys_sync+0xe/0x20 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2f19d8eba9
RSP: 002b:00007f2f1ab62038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f2f19fd5fa0 RCX: 00007f2f19d8eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f2f19fd5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2f19fd6038 R14: 00007f2f19fd5fa0 R15: 00007fff3a9c5408
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5618:
 #0: ffff88814d7f50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036d32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by udevd/5859:
 #0: ffff888142fca358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945
1 lock held by syz.2.3106/15143:
 #0: ffff888142fca358 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ac/0x340 block/bdev.c:1288
1 lock held by syz.1.4050/18050:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf60/0xfa0 kernel/hung_task.c:495
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 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: 5848 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:update_sg_lb_stats kernel/sched/fair.c:-1 [inline]
RIP: 0010:update_sd_lb_stats kernel/sched/fair.c:11024 [inline]
RIP: 0010:sched_balance_find_src_group kernel/sched/fair.c:11283 [inline]
RIP: 0010:sched_balance_rq+0xdd7/0x57a0 kernel/sched/fair.c:11745
Code: 74 08 4c 89 f7 e8 f9 ad 8e 00 4d 39 3e 0f 83 0e fc ff ff 42 80 3c 2b 00 74 08 4c 89 f7 e8 d1 ae 8e 00 4d 89 3e e9 f7 fb ff ff <49> 89 fe 48 89 f3 44 89 e7 e8 fb 00 03 00 85 c0 0f 84 ac 00 00 00
RSP: 0018:ffffc900040cf340 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88802f321e40
RDX: 0000000000000000 RSI: ffff8880b873a058 RDI: 1ffff110170e740b
RBP: ffffc900040cf7f0 R08: ffffc900040cf69f R09: 0000000000000000
R10: ffffc900040cf648 R11: fffff52000819ed4 R12: 0000000000000001
R13: ffffc900040cf670 R14: ffff8880b8739f80 R15: dffffc0000000000
FS:  00005555873c3500(0000) GS:ffff8881258a7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557a9855c8 CR3: 00000000770c6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 sched_balance_newidle+0x6b6/0x1030 kernel/sched/fair.c:12832
 pick_next_task_fair+0x40/0xba0 kernel/sched/fair.c:8909
 __pick_next_task+0xe4/0x450 kernel/sched/core.c:6004
 pick_next_task kernel/sched/core.c:6089 [inline]
 __schedule+0x7a4/0x4cc0 kernel/sched/core.c:6905
 __schedule_loop kernel/sched/core.c:7046 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7061
 do_nanosleep+0x1c5/0x610 kernel/time/hrtimer.c:2116
 hrtimer_nanosleep+0x169/0x360 kernel/time/hrtimer.c:2163
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1398 [inline]
 __se_sys_clock_nanosleep+0x2f1/0x380 kernel/time/posix-timers.c:1375
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0b459c1423
Code: 1f 84 00 00 00 00 00 83 ff 03 74 7b 83 ff 02 b8 fa ff ff ff 49 89 ca 0f 44 f8 80 3d 3e 71 1e 00 00 74 14 b8 e6 00 00 00 0f 05 <f7> d8 c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 28 48 89 54 24 10
RSP: 002b:00007ffe8a0c4a38 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0b459c1423
RDX: 00007ffe8a0c4a50 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 000000002a7e296a R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffe8a0c4ea0
R13: 0000000000000004 R14: 00007ffe8a0c4a8c R15: 00007ffe8a0c4b20
 </TASK>