INFO: task syz.0.2878:24075 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.2878      state:D stack:28760 pid:24075 tgid:24074 ppid:23882  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 __schedule+0x17ba/0x5670
 schedule+0x164/0x360
 schedule_preempt_disabled+0x13/0x30
 __mutex_lock+0x7f7/0x1550
 sync_bdevs+0x27e/0x470
 __ia32_sys_sync+0xc5/0x120
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa1e199cdd9
RSP: 002b:00007fa1e2801028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fa1e1c15fa0 RCX: 00007fa1e199cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fa1e1c15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa1e1c16038 R14: 00007fa1e1c15fa0 R15: 00007ffdd3e19328
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5438:
 #0: ffff88810f9160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc9000346b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45f/0x1490
1 lock held by udevd/5607:
 #0: ffff8881098ad350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
1 lock held by syz.0.2878/24075:
 #0: ffff8881098ad350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x27e/0x470
2 locks held by syz.3.3809/27960:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 sys_info+0x135/0x170
 watchdog+0xfd3/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5664 Comm: kworker/u8:3 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:__lock_acquire+0x144b/0x2cf0
Code: ff 85 db 74 04 90 0f 0b 90 31 ed 65 48 8b 05 ac ed 96 11 48 3b 84 24 e0 00 00 00 0f 85 69 16 00 00 89 e8 48 81 c4 e8 00 00 00 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 46 c7 08 0a cc 4d 85 ff 4c 8b 6c
RSP: 0018:ffffc900056df218 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 00000000cbcf2d62 RCX: 0000000000000000
RDX: 00000000a376f302 RSI: 0000000065b52455 RDI: ffff88810ac51d80
RBP: 0000000000000001 R08: ffffffff8176e116 R09: ffffffff8e95cda0
R10: ffffc900056df448 R11: fffff52000adbe95 R12: ffff88810ac529b0
R13: ffff88810ac529b0 R14: ffff88810ac51d80 R15: 0000000000000004
FS:  0000000000000000(0000) GS:ffff8882a9296000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe0c1fff000 CR3: 00000001b27de000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 unwind_next_frame+0xc3/0x2550
 __unwind_start+0x5b8/0x760
 arch_stack_walk+0xe3/0x150
 stack_trace_save+0xa9/0x100
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x35c/0x760
 batadv_tvlv_container_ogm_append+0x158/0x4f0
 batadv_iv_ogm_schedule+0x290/0xf50
 batadv_iv_send_outstanding_bat_ogm_packet+0x6c8/0x7e0
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
