[syzbot] unregister_netdevice: waiting for DEV to become free (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    9c8774e629a1 net: eql: Use kzalloc instead of kmalloc/memset
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17bf6cc8f00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9eb259db6b1893cf
dashboard link: https://syzkaller.appspot.com/bug?extid=5e70d01ee8985ae62a3b
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1136d592f00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1193ae64f00000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=167c33a2f00000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=157c33a2f00000
console output: https://syzkaller.appspot.com/x/log.txt?x=117c33a2f00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5e70d01ee8985ae62a3b@xxxxxxxxxxxxxxxxxxxxxxxxx

iwpm_register_pid: Unable to send a nlmsg (client = 2)
infiniband syj1: RDMA CMA: cma_listen_on_dev, error -98
unregister_netdevice: waiting for vlan0 to become free. Usage count = 2


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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches