R13: 00007ffc67808eaf R14: 00007f952df639c0 R15: 000000000119bf8c
============================================
WARNING: possible recursive locking detected
4.19.167-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.1/16858 is trying to acquire lock:
00000000ad9621b8 (rtnl_mutex){+.+.}, at: hsr_dev_destroy+0x1b/0xb0 net/hsr/hsr_device.c:373

but task is already holding lock:
00000000ad9621b8 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
00000000ad9621b8 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4775

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(rtnl_mutex);
  lock(rtnl_mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

1 lock held by syz-executor.1/16858:
 #0: 00000000ad9621b8 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
 #0: 00000000ad9621b8 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4775

stack backtrace:
CPU: 1 PID: 16858 Comm: syz-executor.1 Not tainted 4.19.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2fe lib/dump_stack.c:118
 print_deadlock_bug kernel/locking/lockdep.c:1763 [inline]
 check_deadlock kernel/locking/lockdep.c:1807 [inline]
 validate_chain kernel/locking/lockdep.c:2403 [inline]
 __lock_acquire.cold+0x121/0x57e kernel/locking/lockdep.c:3415
overlayfs: workdir and upperdir must be separate subtrees
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907
 __mutex_lock_common kernel/locking/mutex.c:925 [inline]
 __mutex_lock+0xd7/0x1260 kernel/locking/mutex.c:1072
 hsr_dev_destroy+0x1b/0xb0 net/hsr/hsr_device.c:373
 register_netdevice+0x901/0x10f0 net/core/dev.c:8778
 hsr_dev_finalize+0x4f5/0x770 net/hsr/hsr_device.c:491
 hsr_newlink+0x27d/0x3e0 net/hsr/hsr_netlink.c:78
 rtnl_newlink+0x1027/0x15b0 net/core/rtnetlink.c:3141
 rtnetlink_rcv_msg+0x453/0xb80 net/core/rtnetlink.c:4778
 netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2455
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x6bb/0xc40 net/netlink/af_netlink.c:1909
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xc3/0x120 net/socket.c:632
 ___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2115
 __sys_sendmsg net/socket.c:2153 [inline]
 __do_sys_sendmsg net/socket.c:2162 [inline]
 __se_sys_sendmsg net/socket.c:2160 [inline]
 __x64_sys_sendmsg+0x132/0x220 net/socket.c:2160
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45e219
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f952df62c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045e219
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00007f952df62ca0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000a
R13: 00007ffc67808eaf R14: 00007f952df639c0 R15: 000000000119bf8c