syzbot

INFO: task syz.0.27:4647 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.27        state:D stack:27152 pid: 4647 ppid:  4625 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 rwsem_down_read_slowpath+0x548/0x9d0 kernel/locking/rwsem.c:1055
 __down_read_common kernel/locking/rwsem.c:1239 [inline]
 __down_read kernel/locking/rwsem.c:1252 [inline]
 down_read+0x96/0x2e0 kernel/locking/rwsem.c:1500
 iterate_supers+0xa4/0x1d0 fs/super.c:716
 ksys_sync+0x9d/0x170 fs/sync.c:102
 __ia32_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1c1cb7deb9
RSP: 002b:00007f1c1c1e1028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f1c1cdf8fa0 RCX: 00007f1c1cb7deb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1c1cdf8fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c1cdf9038 R14: 00007f1c1cdf8fa0 R15: 00007ffefc215548
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:4/1276:
2 locks held by getty/3947:
 #0: ffff88802cd0f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
3 locks held by kworker/0:6/4295:
 #0: ffff88802bed3138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000316fd00
 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: 
ffffffff8d43c748 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x1540 net/ipv6/addrconf.c:4110
1 lock held by syz.0.17/4337:
3 locks held by kworker/1:22/4354:
 #0: ffff88802bed3138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc900033cfd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffff88807e1f0ee0 (&r->consumer_lock#2){+.+.}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:369 [inline]
 #2: ffff88807e1f0ee0 (&r->consumer_lock#2){+.+.}-{2:2}, at: ptr_ring_consume_bh include/linux/ptr_ring.h:365 [inline]
 #2: ffff88807e1f0ee0 (&r->consumer_lock#2){+.+.}-{2:2}, at: wg_packet_decrypt_worker+0x980/0xe00 drivers/net/wireguard/receive.c:506
1 lock held by syz.1.18/4379:
1 lock held by syz.2.19/4409:
1 lock held by syz.3.20/4431:
1 lock held by syz.4.21/4461:
1 lock held by syz.5.22/4497:
1 lock held by syz.6.23/4525:
1 lock held by syz.7.24/4553:
1 lock held by syz.8.25/4590:
1 lock held by syz.9.26/4618:
1 lock held by syz.0.27/4647:
 #0: ffff88807cf860e0 (&type->s_umount_key#73){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716