INFO: task syz-executor.0:17657 blocked for more than 143 seconds.
      Not tainted 6.4.0-rc7-syzkaller-00234-g547cc9be86f4 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:24544 pid:17657 ppid:5031   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5343 [inline]
 __schedule+0x187b/0x4900 kernel/sched/core.c:6669
 schedule+0xc3/0x180 kernel/sched/core.c:6745
 wb_wait_for_completion+0x166/0x290 fs/fs-writeback.c:192
 sync_inodes_sb+0x297/0xab0 fs/fs-writeback.c:2730
 iterate_supers+0x12b/0x1e0 fs/super.c:745
 ksys_sync+0xbd/0x1c0 fs/sync.c:102
 __do_sys_sync+0xe/0x20 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd1a788c389
RSP: 002b:00007fd1a8624168 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fd1a79abf80 RCX: 00007fd1a788c389
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fd1a78d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd73c9119f R14: 00007fd1a8624300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/13:
 #0: ffffffff8cf276f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518
1 lock held by rcu_tasks_trace/14:
 #0: ffffffff8cf27ab0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:518
1 lock held by khungtaskd/28:
 #0: ffffffff8cf27520 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:5/1126:
2 locks held by getty/4752:
 #0: ffff888028a43098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900015802f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6ab/0x1db0 drivers/tty/n_tty.c:2176
2 locks held by syz-executor.3/13663:
 #0: ffff88807bd514e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x254/0x2f0 fs/file.c:1047
 #1: ffff88802e04f200 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:785 [inline]
 #1: ffff88802e04f200 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: ext4_dio_read_iter fs/ext4/file.c:78 [inline]
 #1: ffff88802e04f200 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: ext4_file_read_iter+0x294/0x670 fs/ext4/file.c:145
2 locks held by syz-executor.0/17657:
 #0: ffff88807be580e0 (&type->s_umount_key#31){++++}-{3:3}, at: iterate_supers+0xb0/0x1e0 fs/super.c:743
 #1: ffff88801f33e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline]
 #1: ffff88801f33e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x278/0xab0 fs/fs-writeback.c:2728
2 locks held by syz-executor.0/17845:
 #0: ffff88807be580e0 (&type->s_umount_key#31){++++}-{3:3}, at: iterate_supers+0xb0/0x1e0 fs/super.c:743
 #1: ffff88801f33e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline]
 #1: ffff88801f33e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x278/0xab0 fs/fs-writeback.c:2728
2 locks held by syz-executor.0/17937:
 #0: ffff88807be580e0 (&type->s_umount_key#31){++++}-{3:3}, at: iterate_supers+0xb0/0x1e0 fs/super.c:743
 #1: ffff88801f33e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:364 [inline]
 #1: ffff88801f33e7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x278/0xab0 fs/fs-writeback.c:2728

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.4.0-rc7-syzkaller-00234-g547cc9be86f4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x498/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x187/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xec2/0xf00 kernel/hung_task.c:379
 kthread+0x2b8/0x350 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 10 Comm: kworker/u4:0 Not tainted 6.4.0-rc7-syzkaller-00234-g547cc9be86f4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Workqueue: bat_events batadv_dat_purge
RIP: 0010:__batadv_dat_purge net/batman-adv/distributed-arp-table.c:175 [inline]
RIP: 0010:batadv_dat_purge+0x104/0x3c0 net/batman-adv/distributed-arp-table.c:205
Code: c1 e7 06 49 03 7d 00 48 89 7c 24 18 e8 55 90 3c 00 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 1f cb 65 f7 4c 8b 3b <4d> 85 ff 41 bd 30 75 00 00 0f 84 b2 01 00 00 49 83 c7 e8 0f 84 a8
RSP: 0018:ffffc900000f7bf8 EFLAGS: 00000246
RAX: 1ffff110050d80e0 RBX: ffff8880286c0700 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc900000f7b80
RBP: 00000000000000e0 R08: dffffc0000000000 R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88807b1dfec8 R14: dffffc0000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f309786c580 CR3: 000000000cd30000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 process_one_work+0x8a0/0x10e0 kernel/workqueue.c:2408
 worker_thread+0xa63/0x1210 kernel/workqueue.c:2555
 kthread+0x2b8/0x350 kernel/kthread.c:379
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>