Re: [syzbot] [net?] unregister_netdevice: waiting for DEV to become free (9)

From: syzbot

Date: Tue Sep 15 2026 - 09:40:08 EST


syzbot has found a reproducer for the following issue on:

HEAD commit: 5445d6419962 arm64: Don't read GMID_EL1 when MTE is disabled
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=1250428e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=56ed23170c168d4c
dashboard link: https://syzkaller.appspot.com/bug?extid=e2af46126e0644cbebdd
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15b32471580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d742d1580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e8b70e3bd109/disk-5445d641.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e5227e56ac93/vmlinux-5445d641.xz
kernel image: https://storage.googleapis.com/syzbot-assets/54905f78be59/Image-5445d641.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e2af46126e0644cbebdd@xxxxxxxxxxxxxxxxxxxxxxxxx

unregister_netdevice: waiting for netdevsim2 to become free. Usage count = 2
ref_tracker: netdev@000000004118ac35 has 1/1 users at
__netdev_tracker_alloc include/linux/netdevice.h:4528 [inline]
netdev_tracker_alloc+0x68/0xb4 include/linux/netdevice.h:4540
fib_create_info+0x15cc/0x2184 net/ipv4/fib_semantics.c:1524
fib_table_insert+0xa4/0x12bc net/ipv4/fib_trie.c:1212
fib_magic+0x26c/0x344 net/ipv4/fib_frontend.c:1147
fib_add_ifaddr+0x114/0x500 net/ipv4/fib_frontend.c:1169
fib_inetaddr_event+0x114/0x1c0 net/ipv4/fib_frontend.c:1483
notifier_call_chain+0x1a4/0x624 kernel/notifier.c:85
blocking_notifier_call_chain+0x70/0xa0 kernel/notifier.c:380
__inet_insert_ifa+0x87c/0xa74 net/ipv4/devinet.c:566
inet_rtm_newaddr+0xba4/0x1140 net/ipv4/devinet.c:1001
rtnetlink_rcv_msg+0x66c/0x9bc net/core/rtnetlink.c:7132
netlink_rcv_skb+0x238/0x414 net/netlink/af_netlink.c:2556
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:7159
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x600/0x7f8 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x648/0x948 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:800 [inline]
__sock_sendmsg+0xc8/0x17c net/socket.c:815

netdevsim netdevsim2 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0


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If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.