Re: WARNING in xfrm_alloc_compat

[Steffen Klassert]

Same here, Dmitry please look into it.

I guess we can just remove the WARN_ON() that
triggeres here.

On Mon, Oct 26, 2020 at 06:58:28AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    f11901ed Merge tag 'xfs-5.10-merge-7' of git://git.kernel...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17b35564500000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=fb79b5c2dc1e69e3
> dashboard link: https://syzkaller.appspot.com/bug?extid=a7e701c8385bd8543074
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+a7e701c8385bd8543074@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> netlink: 404 bytes leftover after parsing attributes in process `syz-executor.4'.
> ------------[ cut here ]------------
> unsupported nla_type 0
> WARNING: CPU: 0 PID: 9953 at net/xfrm/xfrm_compat.c:279 xfrm_xlate64_attr net/xfrm/xfrm_compat.c:279 [inline]
> WARNING: CPU: 0 PID: 9953 at net/xfrm/xfrm_compat.c:279 xfrm_xlate64 net/xfrm/xfrm_compat.c:300 [inline]
> WARNING: CPU: 0 PID: 9953 at net/xfrm/xfrm_compat.c:279 xfrm_alloc_compat+0xf39/0x10d0 net/xfrm/xfrm_compat.c:327
> Modules linked in:
> CPU: 0 PID: 9953 Comm: syz-executor.4 Not tainted 5.9.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:xfrm_xlate64_attr net/xfrm/xfrm_compat.c:279 [inline]
> RIP: 0010:xfrm_xlate64 net/xfrm/xfrm_compat.c:300 [inline]
> RIP: 0010:xfrm_alloc_compat+0xf39/0x10d0 net/xfrm/xfrm_compat.c:327
> Code: de e8 4b 68 d3 f9 84 db 0f 85 b0 f8 ff ff e8 2e 70 d3 f9 8b 74 24 08 48 c7 c7 40 b9 51 8a c6 05 f7 0d 3c 05 01 e8 b7 db 0e 01 <0f> 0b e9 8d f8 ff ff e8 0b 70 d3 f9 8b 14 24 48 c7 c7 00 b9 51 8a
> RSP: 0018:ffffc9000bb4f4b8 EFLAGS: 00010282
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000040000 RSI: ffffffff8158cf25 RDI: fffff52001769e89
> RBP: 00000000000001a0 R08: 0000000000000001 R09: ffff8880b9e2005b
> R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffa1
> R13: ffff88802ed1d8f8 R14: ffff888014403c80 R15: ffff88801514fc80
> FS:  00007f188bbe6700(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000000074b698 CR3: 000000001aabe000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  xfrm_alloc_userspi+0x66a/0xa30 net/xfrm/xfrm_user.c:1388
>  xfrm_user_rcv_msg+0x42f/0x8b0 net/xfrm/xfrm_user.c:2752
>  netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
>  xfrm_netlink_rcv+0x6b/0x90 net/xfrm/xfrm_user.c:2764
>  netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
>  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
>  netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
>  sock_sendmsg_nosec net/socket.c:651 [inline]
>  sock_sendmsg+0xcf/0x120 net/socket.c:671
>  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
>  ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
>  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
>  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
>  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> RIP: 0033:0x45de59
> 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:00007f188bbe5c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 000000000002e640 RCX: 000000000045de59
> RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003
> RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
> R13: 000000000169fb7f R14: 00007f188bbe69c0 R15: 000000000118bf2c
> 
> 
> ---
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