INFO: task syz.6.755:9192 blocked for more than 144 seconds.
      Not tainted 6.14.0-rc4-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.755       state:D stack:25824 pid:9192  tgid:9181  ppid:7536   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914
 __mutex_lock_common kernel/locking/mutex.c:662 [inline]
 __mutex_lock+0x817/0x1010 kernel/locking/mutex.c:730
 sync_bdevs+0x1ae/0x340 block/bdev.c:1246
 ksys_sync+0xe2/0x1c0 fs/sync.c:105
 __do_sys_sync+0xe/0x20 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe03618d169
RSP: 002b:00007fe036f77038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fe0363a6240 RCX: 00007fe03618d169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fe0363a6240 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fe0363a6240 R15: 00007ffeb2f83818
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8eb38f60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746
2 locks held by getty/5578:
 #0: ffff88803193c0a0 (&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+0x616/0x1770 drivers/tty/n_tty.c:2211
1 lock held by udevd/5818:
 #0: ffff8880256e34c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xf0/0xc50 block/bdev.c:903
3 locks held by kworker/u8:15/8814:
 #0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
 #0: ffff88801b089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x98b/0x18e0 kernel/workqueue.c:3317
 #1: ffffc90003f2fc60 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
 #1: ffffc90003f2fc60 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9c6/0x18e0 kernel/workqueue.c:3317
 #2: ffffffff8eb3e300 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3741
1 lock held by syz.6.755/9192:
 #0: ffff8880256e34c8 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x1ae/0x340 block/bdev.c:1246
1 lock held by syz.0.991/10382:
 #0: ffff8880256e34c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xf0/0xc50 block/bdev.c:903
2 locks held by syz.7.1000/10417:
 #0: ffff88807b43e808 (&sb->s_type->i_mutex_key#9){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:877 [inline]
 #0: ffff88807b43e808 (&sb->s_type->i_mutex_key#9){+.+.}-{4:4}, at: __sock_release net/socket.c:646 [inline]
 #0: ffff88807b43e808 (&sb->s_type->i_mutex_key#9){+.+.}-{4:4}, at: sock_close+0x90/0x240 net/socket.c:1398
 #1: ffffffff8eb3e438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:334 [inline]
 #1: ffffffff8eb3e438 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x820 kernel/rcu/tree_exp.h:996

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0x1058/0x10a0 kernel/hung_task.c:399
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111