On Tue, Feb 25, 2020 at 09:39:10PM -0800, syzbot wrote:

Hello,

syzbot found the following crash on:

HEAD commit:    6132c1d9 net: core: devlink.c: Hold devlink->lock from the..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=16978909e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3b8906eb6a7d6028
dashboard link: https://syzkaller.appspot.com/bug?extid=55de90ab5f44172b0c90
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12808281e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=134ca6fde00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+55de90ab5f44172b0c90@syzkaller.appspotmail.com

iwpm_register_pid: Unable to send a nlmsg (client = 2)
infiniband syz1: RDMA CMA: cma_listen_on_dev, error -98
netlink: 'syz-executor639': attribute type 1 has an invalid length.
8021q: adding VLAN 0 to HW filter on device bond1
bond1: (slave gretap1): making interface the new active one
======================================================
WARNING: possible circular locking dependency detected
5.6.0-rc2-syzkaller #0 Not tainted
syz-executor639/9689 is trying to acquire lock:
ffffffff8a5d2a60 (lock#3){+.+.}, at: cma_netdev_callback+0xc6/0x380 drivers/infiniband/core/cma.c:4605

but task is already holding lock:
ffffffff8a74da00 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
ffffffff8a74da00 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x405/0xaf0 net/core/rtnetlink.c:5433

Bernard, this is a siw bug too, it is not allowed to get RTNL in
siw_create_listen() (though this is probably for silly reasons and
could be fixed)

It is not easy to get this into the lockdep, I'll send a different
patch too

Jason