Subject: WARNING in nft_request_module

From: syzbot <[email-masked]>
Date: Wed, 15 Jan 2020 16:25:12 -0800

Hello,

syzbot found the following crash on:

HEAD commit:    51d69817 Merge tag 'platform-drivers-x86-v5.5-3' of git://..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17645c35e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfbb8fa33f49f9f3
dashboard link: https://syzkaller.appspot.com/bug?extid=0e63ae76d117ae1c3a01
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/  
c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11123421e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15b873fee00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

netlink: 760 bytes leftover after parsing attributes in process  
`syz-executor332'.
------------[ cut here ]------------
truncated: 'nft-expr-0-���LMMR�~��*�{���F����Dc��H�c(��?V�' (len  
209)
WARNING: CPU: 1 PID: 8621 at net/netfilter/nf_tables_api.c:588  
nft_request_module+0x103/0x110 net/netfilter/nf_tables_api.c:588
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 8621 Comm: syz-executor332 Not tainted 5.5.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1fb/0x318 lib/dump_stack.c:118
  panic+0x264/0x7a9 kernel/panic.c:221
  __warn+0x209/0x210 kernel/panic.c:582
  report_bug+0x1b6/0x2f0 lib/bug.c:195
  fixup_bug arch/x86/kernel/traps.c:174 [inline]
  do_error_trap+0xda/0x440 arch/x86/kernel/traps.c:267
  do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:286
  invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:nft_request_module+0x103/0x110 net/netfilter/nf_tables_api.c:588
Code: 88 00 00 00 75 28 48 8d 65 f0 5b 41 5e 5d c3 e8 a3 3b e0 fa 48 8d 74  
24 50 48 c7 c7 e0 ba e2 88 44 89 f2 31 c0 e8 ad 47 b2 fa <0f> 0b eb c5 e8  
44 48 b2 fa 0f 1f 40 00 55 48 89 e5 41 57 41 56 41
RSP: 0018:ffffc90001ea75b0 EFLAGS: 00010246
RAX: a0c74c5486a24900 RBX: ffffffff89353700 RCX: ffff88808f06c1c0
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000282
RBP: ffffc90001ea7650 R08: ffff88808f06ca18 R09: fffffbfff13cd132
R10: fffffbfff13cd132 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880a3f8f168 R14: 00000000000000d1 R15: ffffffff8936d1f0
  nft_expr_type_request_module net/netfilter/nf_tables_api.c:2320 [inline]
  nft_expr_type_get net/netfilter/nf_tables_api.c:2345 [inline]
  nf_tables_expr_parse+0x308/0x9e0 net/netfilter/nf_tables_api.c:2420
  nf_tables_newrule+0xefb/0x2d90 net/netfilter/nf_tables_api.c:3037
  nfnetlink_rcv_batch net/netfilter/nfnetlink.c:433 [inline]
  nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:543 [inline]
  nfnetlink_rcv+0xecf/0x1e50 net/netfilter/nfnetlink.c:561
  netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
  netlink_unicast+0x767/0x920 net/netlink/af_netlink.c:1328
  netlink_sendmsg+0xa2c/0xd50 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:639 [inline]
  sock_sendmsg net/socket.c:659 [inline]
  ____sys_sendmsg+0x4f7/0x7f0 net/socket.c:2330
  ___sys_sendmsg net/socket.c:2384 [inline]
  __sys_sendmsg+0x1ed/0x290 net/socket.c:2417
  __do_sys_sendmsg net/socket.c:2426 [inline]
  __se_sys_sendmsg net/socket.c:2424 [inline]
  __x64_sys_sendmsg+0x7f/0x90 net/socket.c:2424
  do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440619
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffeca951478 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440619
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000005
RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401ea0
R13: 0000000000401f30 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

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