INFO: task syz.1.166:6549 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.166       state:D stack:27240 pid:6549  ppid:5792   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6832
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6b7/0xcc0 kernel/locking/mutex.c:747
 sync_bdevs+0x1af/0x330 block/bdev.c:1059
 ksys_sync+0xba/0x150 fs/sync.c:105
 __ia32_sys_sync+0xe/0x20 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f044c98eec9
RSP: 002b:00007f044d7bf038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f044cbe5fa0 RCX: 00007f044c98eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f044cbe5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f044cbe6038 R14: 00007f044cbe5fa0 R15: 00007ffd23b63088
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8cd2ff20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
3 locks held by kworker/u4:6/1084:
2 locks held by getty/5547:
 #0: ffff88802cacd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000328b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x425/0x1380 drivers/tty/n_tty.c:2217
1 lock held by syz-executor/5791:
 #0: ffff88807bf240e0 (&type->s_umount_key#99){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88807bf240e0 (&type->s_umount_key#99){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88807bf240e0 (&type->s_umount_key#99){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by udevd/6120:
 #0: ffff8881413b54c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x121/0x600 block/bdev.c:788
1 lock held by syz.1.166/6549:
 #0: ffff8881413b54c8 (&disk->open_mutex){+.+.}-{3:3}, at: sync_bdevs+0x1af/0x330 block/bdev.c:1059
1 lock held by syz.3.618/8191:

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x39b/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf41/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8191 Comm: syz.3.618 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rb_link_node include/linux/rbtree.h:65 [inline]
RIP: 0010:rb_add_augmented_cached include/linux/rbtree_augmented.h:82 [inline]
RIP: 0010:__enqueue_entity+0x47c/0x4e0 kernel/sched/fair.c:841
Code: 7c 24 10 75 36 eb 5a ba 18 00 00 00 4c 89 ff 31 f6 e8 98 9c 7c 00 48 b8 00 00 00 00 00 fc ff df 41 80 3c 06 00 48 8b 5c 24 08 <74> 08 48 89 df e8 1a 9b 7c 00 4c 89 3b 48 8b 1c 24 48 83 c3 58 48
RSP: 0018:ffffc9000376f1b8 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff888053c5c850 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805f833ca8
RBP: 0000000000000000 R08: ffff88805f833ca7 R09: 0000000000000000
R10: ffff88805f833c90 R11: ffffed100bf06795 R12: ffff88805f833ce8
R13: ffff88805f833c80 R14: 1ffff1100a78b90a R15: ffff88805f833c90
FS:  00007f68decc66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6c711b6358 CR3: 0000000077449000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 put_prev_entity+0x62/0x200 kernel/sched/fair.c:5505
 put_prev_task_fair+0x4b/0x70 kernel/sched/fair.c:8571
 put_prev_task kernel/sched/sched.h:2306 [inline]
 put_prev_task_balance kernel/sched/core.c:5984 [inline]
 pick_next_task kernel/sched/core.c:6119 [inline]
 __schedule+0x2789/0x44d0 kernel/sched/core.c:6661
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0xfa/0x110 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __wake_up_common_lock kernel/sched/wait.c:140 [inline]
 __wake_up_sync_key+0x11f/0x190 kernel/sched/wait.c:213
 __unix_dgram_recvmsg+0x49c/0xd60 net/unix/af_unix.c:2437
 sock_recvmsg_nosec+0x82/0xd0 net/socket.c:1046
 ____sys_recvmsg+0x49b/0x5b0 net/socket.c:2812
 ___sys_recvmsg+0x1b6/0x510 net/socket.c:2856
 do_recvmmsg+0x360/0x7d0 net/socket.c:2950
 __sys_recvmmsg net/socket.c:3029 [inline]
 __do_sys_recvmmsg net/socket.c:3052 [inline]
 __se_sys_recvmmsg net/socket.c:3045 [inline]
 __x64_sys_recvmmsg+0x191/0x240 net/socket.c:3045
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f68ddd8eec9
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:00007f68decc6038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f68ddfe6090 RCX: 00007f68ddd8eec9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007f68dde11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f68ddfe6128 R14: 00007f68ddfe6090 R15: 00007fffada015c8
 </TASK>