INFO: task syz.2.762:7237 blocked for more than 143 seconds.
      Not tainted 5.15.167-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.762       state:D stack:25920 pid: 7237 ppid:  6702 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 wb_wait_for_completion+0x164/0x290 fs/fs-writeback.c:191
 sync_inodes_sb+0x293/0xab0 fs/fs-writeback.c:2770
 iterate_supers+0x127/0x1e0 fs/super.c:716
 ksys_sync+0xb9/0x1c0 fs/sync.c:102
 __do_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f175124def9
RSP: 002b:00007f174f6c6038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1751405f80 RCX: 00007f175124def9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f17512c0b76 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1751405f80 R15: 00007ffc79b5eaf8
 </TASK>

Showing all locks held in the system:
3 locks held by ksoftirqd/1/20:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3332:
 #0: ffff888028f85098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000229b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:8/3728:
 #0: ffff88814439c938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003397d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
2 locks held by kworker/u4:12/4271:
 #0: ffff888017079138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003217d20 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
3 locks held by kworker/0:20/5001:
 #0: ffff88801c001538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc900013cfd20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff8880239d82a8 (&dev->power.lock){-...}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:388 [inline]
 #2: ffff8880239d82a8 (&dev->power.lock){-...}-{2:2}, at: rpm_idle+0x4c9/0x8b0 drivers/base/power/runtime.c:497
1 lock held by syz.3.746/7180:
 #0: ffff88807bc26460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x29a/0xe50 fs/read_write.c:590
2 locks held by syz.2.762/7237:
 #0: ffff88807bc260e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz.4.934/7845:
 #0: ffff88807bc260e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz.2.995/8046:
 #0: ffff88807bc260e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz.3.1002/8073:
 #0: ffff88807bc260e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz.0.1041/8224:
 #0: ffff88807bc260e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz.1.1327/9150:
 #0: ffff88807bc260e0 (&type->s_umount_key#32){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880204467d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9467 Comm: kworker/u4:24 Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: bat_events batadv_nc_worker
RIP: 0010:rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
Code: c1 03 38 c1 0f 8c 72 ff ff ff 48 89 df e8 93 5b b8 f7 e9 65 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 e8 6b 91 6e f7 <e8> 66 91 6e f7 48 c7 c7 60 fc 91 8c 31 f6 31 d2 b9 02 00 00 00 45
RSP: 0018:ffffc90003857bf0 EFLAGS: 00000293
RAX: ffffffff8a11c905 RBX: ffff888053b3d2a0 RCX: ffff888066f33b80
RDX: 0000000000000000 RSI: ffffffff8a8b3da0 RDI: ffffffff8ad904c0
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1bd2c16
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000254
R13: dffffc0000000000 R14: ffff888051bf4c80 R15: ffff8880621e7ec0
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3f7f97 CR3: 0000000072d71000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc1/0x5b0 net/batman-adv/network-coding.c:723
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>