[syzbot] WARNING: locking bug in inet_send_prepare

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    a5541c0811a0 Merge branch 'for-next/core' into for-kernelci
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=124dd2a2480000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cbd4e584773e9397
dashboard link: https://syzkaller.appspot.com/bug?extid=52866e24647f9a23403f
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10d322e0480000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1208adc4480000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4b7702208fb9/disk-a5541c08.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9ec0153ec051/vmlinux-a5541c08.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6f8725ad290a/Image-a5541c08.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+52866e24647f9a23403f@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
Looking for class "l2tp_sock" with key l2tp_socket_class, but found a different class "slock-AF_INET6" with the same key
WARNING: CPU: 0 PID: 24577 at kernel/locking/lockdep.c:940 look_up_lock_class+0x158/0x160
Modules linked in:
CPU: 0 PID: 24577 Comm: syz-executor105 Not tainted 6.1.0-rc8-syzkaller-33330-ga5541c0811a0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : look_up_lock_class+0x158/0x160
lr : look_up_lock_class+0x154/0x160 kernel/locking/lockdep.c:937
sp : ffff800014a7b980
x29: ffff800014a7b980 x28: 0000000000000000 x27: 0000000000000000
x26: ffff0000d0864bb0 x25: ffff80000b22ff14 x24: 0000000000000000
x23: ffff80000eec8000 x22: 0000000000000001 x21: ffff80000f1c3018
x20: 0000000000000000 x19: ffff80000dc27c18 x18: 0000000000000000
x17: 6f6620747562202c x16: 7373616c635f7465 x15: 6b636f735f707432
x14: 6c2079656b206874 x13: 205d373735343254 x12: 5b5d313634303832
x11: ff808000081c4d64 x10: 0000000000000000 x9 : ad3022ef6adb7200
x8 : ad3022ef6adb7200 x7 : 545b5d3136343038 x6 : ffff80000c091ebc
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000100000201 x0 : ffff80000dc27c18
Call trace:
 look_up_lock_class+0x158/0x160
 register_lock_class+0x4c/0x2f8 kernel/locking/lockdep.c:1289
 __lock_acquire+0xa8/0x3084 kernel/locking/lockdep.c:4934
 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
 _raw_spin_lock_bh+0x54/0x6c kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:355 [inline]
 lock_sock_nested+0x88/0xd8 net/core/sock.c:3450
 lock_sock include/net/sock.h:1721 [inline]
 inet_autobind net/ipv4/af_inet.c:177 [inline]
 inet_send_prepare+0x70/0xf4 net/ipv4/af_inet.c:813
 inet6_sendmsg+0x30/0x80 net/ipv6/af_inet6.c:660
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 __sys_sendto+0x1e4/0x280 net/socket.c:2117
 __do_sys_sendto net/socket.c:2129 [inline]
 __se_sys_sendto net/socket.c:2125 [inline]
 __arm64_sys_sendto+0x30/0x44 net/socket.c:2125
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
 el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:584
irq event stamp: 162
hardirqs last  enabled at (161): [<ffff800008038a7c>] local_daif_restore arch/arm64/include/asm/daifflags.h:75 [inline]
hardirqs last  enabled at (161): [<ffff800008038a7c>] el0_svc_common+0x40/0x220 arch/arm64/kernel/syscall.c:107
hardirqs last disabled at (160): [<ffff80000c0844f4>] el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
softirqs last  enabled at (156): [<ffff80000801c82c>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (162): [<ffff80000b22ff14>] spin_lock_bh include/linux/spinlock.h:355 [inline]
softirqs last disabled at (162): [<ffff80000b22ff14>] lock_sock_nested+0x88/0xd8 net/core/sock.c:3450
---[ end trace 0000000000000000 ]---


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